Multidisciplinary Self Assessment Examination Flashcards

Question

Which of the following is a flow-regulated valve? A. Orbis-Sigma valve B. PS Medical Delta valve C. Cordis horizontal-vertical valve D. Codman Hakim programmable valve E. Holter-Hausner valve

Answer 1

**A. Orbis-Sigma valve **

Answer 2

**C. Open-lip schizencephaly **

Answer 3

**D. Cellular migration **

Answer 4

**E. Leucine-enkephalin**

Answer 5

**D. r\.rgilline vasopressin (aqueous Pitressin) intravenously**

Answer 6

**C. Alpha rhythm **

Answer 7

**C. Poor collateral filling of the right globe from the maxillary and facial arteries **

Answer 8

**D. Observation and serial MRI**

Answer 9

**C. Rosenthal fibers **

Answer 10

**C. 6 months**

Answer 11

**D. Ventral suspension (Landau) **

Answer 12

**D. Binocular inferior nasal quadrantanopsia **

Answer 13

**E. All of the above **

Answer 14

**C. Identifying the oligodendroglial component on frozen section is usually facilitated by the classic "fried egg" appearance of the perinuclear halo **

Answer 15

**E. Both A and C **

Answer 16

**A. Occipital poles **

Answer 17

**A. Dorsal cochlear nuclei** ## Footnote The superior olivary nuclei receive the ventral acoustic striae and contain third-order auditory neurons that subsequently project to the contralateral lateral lemniscus. The superior olives are the initial sites of binaural convergence within the auditory pathway (Kandel, pp. 606- 608)

Answer 18

**A. Intraprocedural aneurysmal rupture ** ## Footnote The angiogram depicts a right posterior carotid wall aneurysm as well as extravasation of contrast dye from the aneurysm in a patient about to be treated with GDC embolization (microcatheter evident in internal carotid artery). Intraprocedural aneurysmal rupture is reported to occur in 2 to 8% of patients treated with GDC embolization. It seems to be more prevalent during treatment of smaller aneurysms, especially in the acute phase following SAl-I. It may occur during several phases of the embolization procedure. When the microcatheter is responsible for the rupture, it is important to avoid withdrawing the device prematurely, as the offending device often plugs the ruptured site and prevents additional extravasation of blood. Similarly, if the aneurysm ruptures during the coiling phase, it is important that the clinician deploy the coil in an attempt to seal the leak. In general, once rupture occurs, the remaining aneurysmal sac should be packed as quickly as possible. In refractory cases, temporary or permanent balloon occlusion of the parent vessel or immediate surgical clipping may be warranted (Youmans, pp. 2071-2072).

Answer 19

**A. Myocardial infarction ** ## Footnote Note the prominent ST-segment elevation in leads VI through V" on this ECG, depicting an anterior wallmyocardial infarction. In general, ST-segment and T-wave changes appear over the first minutes to hours of an infarction, and Q waves appear over hours to days. An evolving myocardial infarction may first manifest with peaked '1' waves followed by ST segment elevation and T-wave inversion. Eventually Q waves may appear. In a large anterior wall infarction, these changes are most apparent in leads VI through V(" while in an inferior infarction, these changes often occur in leads II, III, and aVF. Of note, if a patient's T waves are chronically inverted> the peaking may make them appear normal-a process referred to as pseudonormalization. T waves are the least reliable of ST- and T-wave segment abnormalities because many noncardiac events may influence them (i.e., elevated IC+) . Dying myocardial cells release their enzymes into the bloodstream, and the increased concentration should be confirmed in the peripheral blood (Fishman, pp . 9 - 24; Marino, pp. 301-313).

Answer 20

**C. Craniopharyngioma ** ## Footnote The clinical history and MRl are most consistent with a cystic craniopharyngioma. The modestly elevated prolactin level is likely the result of the "stalk effect," whereby injury of the hypothalamus or pituitary stalk (i.e., from large tumors) results in modest elevations of prolactin from reduced prolactin inhibitory factor levels (dopamine). As a general rule, prolactin levels> 150 ng/mL are rarely secondary to a stalk effect, whereas levels < 90 usually suggest a stalk injury. Large components of this tumor extend inferiorly into the sphenoid sinus and superiorly into the suprasellar space. Moreover, the optic chiasm appears draped over the rostral margin of the tumor. Although these are worrisome findings that warrant special concern, they are not uncommon with craniopharyngioma. This sagittal MRl shows that the posterior component of this tumor has eroded through a significant portion of the tuberculum sella and clivus, a relatively rare but significant finding. This latter detail is especially concerning, since failure to recognize this degree of bony erosion on preoperative MRl may result in inadvertent injury to major posterior fossa structures (basilar artery, perforating vessels) during transsphenoidal tumor resection. Thyroxin ('1'4) is generally preferred over thyroid extract ('1'.1) because blood levels are often more predictable. This is especially true for patients with concomitant liver injury, as '1'.1 is converted to T4 in the liver. Patients with ci'rrhosis may remain hypothyroid even while taking T.\. Although it is preferable to correct hypothyroidism preoperatively, it is important to correct any cortisol deficiency as well, as premature thyroid replacement can precipitate an adrenal crisis in this group of patients. Thyroxine has been shown to decrease phenytoin levels (Committee on Education in Neurological Surgery, p. 102; Greenberg, pp. 419- 436).

Answer 21

**B. Stalk effect** ## Footnote The clinical history and MRl are most consistent with a cystic craniopharyngioma. The modestly elevated prolactin level is likely the result of the "stalk effect," whereby injury of the hypothalamus or pituitary stalk (i.e., from large tumors) results in modest elevations of prolactin from reduced prolactin inhibitory factor levels (dopamine). As a general rule, prolactin levels> 150 ng/mL are rarely secondary to a stalk effect, whereas levels < 90 usually suggest a stalk injury. Large components of this tumor extend inferiorly into the sphenoid sinus and superiorly into the suprasellar space. Moreover, the optic chiasm appears draped over the rostral margin of the tumor. Although these are worrisome findings that warrant special concern, they are not uncommon with craniopharyngioma. This sagittal MRl shows that the posterior component of this tumor has eroded through a significant portion of the tuberculum sella and clivus, a relatively rare but significant finding. This latter detail is especially concerning, since failure to recognize this degree of bony erosion on preoperative MRl may result in inadvertent injury to major posterior fossa structures (basilar artery, perforating vessels) during transsphenoidal tumor resection. Thyroxin ('1'4) is generally preferred over thyroid extract ('1'.1) because blood levels are often more predictable. This is especially true for patients with concomitant liver injury, as '1'.1 is converted to T4 in the liver. Patients with ci'rrhosis may remain hypothyroid even while taking T.\. Although it is preferable to correct hypothyroidism preoperatively, it is important to correct any cortisol deficiency as well, as premature thyroid replacement can precipitate an adrenal crisis in this group of patients. Thyroxine has been shown to decrease phenytoin levels (Committee on Education in Neurological Surgery, p. 102; Greenberg, pp. 419- 436).

Answer 22

**E. Elevation of serum angiotensin-converting enzyme** ## Footnote Sarcoidosis, not Behget's syndrome, is associated with elevated levels of angiotensin-converting enzyme (Merritt, pp. 121- 122).

Answer 23

**B. Lambert-Eaton syndrome**

Answer 24

**A. Myasthenia gravis **

Answer 25

**E. Myotonia **

Answer 26

**C. Polymyositis **

Answer 27

**D. Carpal tunnel syndrome **

Answer 28

**D. Langerhans' cell histiocytosis** ## Footnote Note the abnormally thickened stalk with high signal intensity on this coronal MRl depicting Langerhans' cell histiocytosis. The etiology of this condition is unlmown, but it is believed to result from overproliferation of an antigen-presenting dendritic cell of bone marrow origin. Although it is usually treated as a neoplastic process, some speculate that it is due to malfunction of the immune system. Other manifestations of this disease may include lytic skull lesions (approximately 80% of cases) as well as hematopoietic, hepatic, and pulmonary abnormalities. A pathognomic finding of this condition on electron microscopy is the presence of Birbeck granules, a unique organelle of the Langerhans' cell (Ramsey, pp. 381- 385; Merritt, p. 872).

Answer 29

**C. Antigen-presenting dendritic cells ** ## Footnote Note the abnormally thickened stalk with high signal intensity on this coronal MRl depicting Langerhans' cell histiocytosis. The etiology of this condition is unlmown, but it is believed to result from overproliferation of an antigen-presenting dendritic cell of bone marrow origin. Although it is usually treated as a neoplastic process, some speculate that it is due to malfunction of the immune system. Other manifestations of this disease may include lytic skull lesions (approximately 80% of cases) as well as hematopoietic, hepatic, and pulmonary abnormalities. A pathognomic finding of this condition on electron microscopy is the presence of Birbeck granules, a unique organelle of the Langerhans' cell (Ramsey, pp. 381- 385; Merritt, p. 872).

Answer 30

**A. Birbeck granules ** ## Footnote Note the abnormally thickened stalk with high signal intensity on this coronal MRl depicting Langerhans' cell histiocytosis. The etiology of this condition is unlmown, but it is believed to result from overproliferation of an antigen-presenting dendritic cell of bone marrow origin. Although it is usually treated as a neoplastic process, some speculate that it is due to malfunction of the immune system. Other manifestations of this disease may include lytic skull lesions (approximately 80% of cases) as well as hematopoietic, hepatic, and pulmonary abnormalities. A pathognomic finding of this condition on electron microscopy is the presence of Birbeck granules, a unique organelle of the Langerhans' cell (Ramsey, pp. 381- 385; Merritt, p. 872).

Answer 31

**C. Acoustic neuroma** ## Footnote Acoustic neuroma. Note the palisading of nuclei (picket fence-like arrangement) separated by an anuclear area (arrow) on this photomicrograph, which depicts a Verocay body (Ellison, pp. 695- 699).

Answer 32

**A. Verocay body ** ## Footnote Acoustic neuroma. Note the palisading of nuclei (picket fence-like arrangement) separated by an anuclear area (arrow) on this photomicrograph, which depicts a Verocay body (Ellison, pp. 695- 699).

Answer 33

**A. Right medial longitudinal fasciculus ** ## Footnote A lesion of the MLF does not allow for transfer of information from the abducens nucleus (CN VI) to the opoculomotor nucleus (CN III) and results in internuclear ophthalmoplegia (INO). It is characterized by deficient adduction during attempted conjugate gaze away from the side of the lvILF lesion and monocular nystagmus of the abducting eye. An i'vILF lesion is on the same side as the eye with the adduction wealmess, and INO is named for the side of the J'vILF lesion. 1\ lesion in the nucleus of CN III would paralyze volitional movements and convergence (Kline, pp. 63-64).

Answer 34

B ## Footnote Compressive lesions of the ulnar nerve at the level of the elbow, forea rm, or wrist can produce a "claw hand" (A) in severe cases. The ulnar half of the flexor digitorum profundus, lumbricals 3 and 4, the dorsal and palmar interossei, and the hypothenar muscles are typically paralyzed. When the metacarpophalangeal joints are extended, the distal and proximal interphalangeal joints cannot be extended because the interossei and half the IUl11bricais are not functional, which results in a "claw-like" posture. Laceration of the ulnar nerve in the wrist leaves the innervation of the ulnar side of the flexor digitorum profundus intact but can also result in a claw hand. There is also loss of abduction of the thumb, so that a piece of paper cannot be held between the side of the thumb and the index finger.

Answer 35

A ## Footnote Compressive lesions of the ulnar nerve at the level of the elbow, forea rm, or wrist can produce a "claw hand" (A) in severe cases. The ulnar half of the flexor digitorum profundus, lumbricals 3 and 4, the dorsal and palmar interossei, and the hypothenar muscles are typically paralyzed. When the metacarpophalangeal joints are extended, the distal and proximal interphalangeal joints cannot be extended because the interossei and half the IUl11bricais are not functional, which results in a "claw-like" posture. Laceration of the ulnar nerve in the wrist leaves the innervation of the ulnar side of the flexor digitorum profundus intact but can also result in a claw hand. There is also loss of abduction of the thumb, so that a piece of paper cannot be held between the side of the thumb and the index finger.

Answer 36

A ## Footnote Compressive lesions of the ulnar nerve at the level of the elbow, forea rm, or wrist can produce a "claw hand" (A) in severe cases. The ulnar half of the flexor digitorum profundus, lumbricals 3 and 4, the dorsal and palmar interossei, and the hypothenar muscles are typically paralyzed. When the metacarpophalangeal joints are extended, the distal and proximal interphalangeal joints cannot be extended because the interossei and half the IUl11bricais are not functional, which results in a "claw-like" posture. Laceration of the ulnar nerve in the wrist leaves the innervation of the ulnar side of the flexor digitorum profundus intact but can also result in a claw hand. There is also loss of abduction of the thumb, so that a piece of paper cannot be held between the side of the thumb and the index finger.

Answer 37

C ## Footnote Compressive lesions of the ulnar nerve at the level of the elbow, forea rm, or wrist can produce a "claw hand" (A) in severe cases. The ulnar half of the flexor digitorum profundus, lumbricals 3 and 4, the dorsal and palmar interossei, and the hypothenar muscles are typically paralyzed. When the metacarpophalangeal joints are extended, the distal and proximal interphalangeal joints cannot be extended because the interossei and half the IUl11bricais are not functional, which results in a "claw-like" posture. Laceration of the ulnar nerve in the wrist leaves the innervation of the ulnar side of the flexor digitorum profundus intact but can also result in a claw hand. There is also loss of abduction of the thumb, so that a piece of paper cannot be held between the side of the thumb and the index finger.

Answer 38

D ## Footnote Compressive lesions of the ulnar nerve at the level of the elbow, forea rm, or wrist can produce a "claw hand" (A) in severe cases. The ulnar half of the flexor digitorum profundus, lumbricals 3 and 4, the dorsal and palmar interossei, and the hypothenar muscles are typically paralyzed. When the metacarpophalangeal joints are extended, the distal and proximal interphalangeal joints cannot be extended because the interossei and half the IUl11bricais are not functional, which results in a "claw-like" posture. Laceration of the ulnar nerve in the wrist leaves the innervation of the ulnar side of the flexor digitorum profundus intact but can also result in a claw hand. There is also loss of abduction of the thumb, so that a piece of paper cannot be held between the side of the thumb and the index finger.

Answer 39

C ## Footnote Compressive lesions of the ulnar nerve at the level of the elbow, forea rm, or wrist can produce a "claw hand" (A) in severe cases. The ulnar half of the flexor digitorum profundus, lumbricals 3 and 4, the dorsal and palmar interossei, and the hypothenar muscles are typically paralyzed. When the metacarpophalangeal joints are extended, the distal and proximal interphalangeal joints cannot be extended because the interossei and half the IUl11bricais are not functional, which results in a "claw-like" posture. Laceration of the ulnar nerve in the wrist leaves the innervation of the ulnar side of the flexor digitorum profundus intact but can also result in a claw hand. There is also loss of abduction of the thumb, so that a piece of paper cannot be held between the side of the thumb and the index finger.

Answer 40

**C. Speech apraxia ** ## Footnote Apraxia is defined as the inability to execute a normal volitional act despite the fact that the motor systems and mental status are relatively intact. Speech apraxia often results from a lesion near the posterior part of the inferior frontal gyrus (approximately area 44), while writing apraxia or dysgraphia results from damage in the left angular gyrus. Dressing apraxia results from damage in the posterior right parietal lobe, while gait apraxia is usually associated with diffuse cerebral disease such as Alzheimer's disease. Lesions that affect the inferomedial part of the temporo-occipital region tend to cause an inability to recognize facial features (pl:osopagnosia), while lesions of either parietal lobe rnay produce astereognosis, in which patients fail to recognize the forms of objects when felt but not when viewed (Brazis, pp. 481-508).

Answer 41

**B. Writing apraxia ** ## Footnote Apraxia is defined as the inability to execute a normal volitional act despite the fact that the motor systems and mental status are relatively intact. Speech apraxia often results from a lesion near the posterior part of the inferior frontal gyrus (approximately area 44), while writing apraxia or dysgraphia results from damage in the left angular gyrus. Dressing apraxia results from damage in the posterior right parietal lobe, while gait apraxia is usually associated with diffuse cerebral disease such as Alzheimer's disease. Lesions that affect the inferomedial part of the temporo-occipital region tend to cause an inability to recognize facial features (pl:osopagnosia), while lesions of either parietal lobe rnay produce astereognosis, in which patients fail to recognize the forms of objects when felt but not when viewed (Brazis, pp. 481-508).

Answer 42

**A. Dressing apncda ** ## Footnote Apraxia is defined as the inability to execute a normal volitional act despite the fact that the motor systems and mental status are relatively intact. Speech apraxia often results from a lesion near the posterior part of the inferior frontal gyrus (approximately area 44), while writing apraxia or dysgraphia results from damage in the left angular gyrus. Dressing apraxia results from damage in the posterior right parietal lobe, while gait apraxia is usually associated with diffuse cerebral disease such as Alzheimer's disease. Lesions that affect the inferomedial part of the temporo-occipital region tend to cause an inability to recognize facial features (pl:osopagnosia), while lesions of either parietal lobe rnay produce astereognosis, in which patients fail to recognize the forms of objects when felt but not when viewed (Brazis, pp. 481-508).

Answer 43

**D. Gait apraxia ** ## Footnote Apraxia is defined as the inability to execute a normal volitional act despite the fact that the motor systems and mental status are relatively intact. Speech apraxia often results from a lesion near the posterior part of the inferior frontal gyrus (approximately area 44), while writing apraxia or dysgraphia results from damage in the left angular gyrus. Dressing apraxia results from damage in the posterior right parietal lobe, while gait apraxia is usually associated with diffuse cerebral disease such as Alzheimer's disease. Lesions that affect the inferomedial part of the temporo-occipital region tend to cause an inability to recognize facial features (pl:osopagnosia), while lesions of either parietal lobe rnay produce astereognosis, in which patients fail to recognize the forms of objects when felt but not when viewed (Brazis, pp. 481-508).

Answer 44

**E. Prosopagnosia ** ## Footnote Apraxia is defined as the inability to execute a normal volitional act despite the fact that the motor systems and mental status are relatively intact. Speech apraxia often results from a lesion near the posterior part of the inferior frontal gyrus (approximately area 44), while writing apraxia or dysgraphia results from damage in the left angular gyrus. Dressing apraxia results from damage in the posterior right parietal lobe, while gait apraxia is usually associated with diffuse cerebral disease such as Alzheimer's disease. Lesions that affect the inferomedial part of the temporo-occipital region tend to cause an inability to recognize facial features (pl:osopagnosia), while lesions of either parietal lobe rnay produce astereognosis, in which patients fail to recognize the forms of objects when felt but not when viewed (Brazis, pp. 481-508).

Answer 45

**F. Astereognosis ** ## Footnote Apraxia is defined as the inability to execute a normal volitional act despite the fact that the motor systems and mental status are relatively intact. Speech apraxia often results from a lesion near the posterior part of the inferior frontal gyrus (approximately area 44), while writing apraxia or dysgraphia results from damage in the left angular gyrus. Dressing apraxia results from damage in the posterior right parietal lobe, while gait apraxia is usually associated with diffuse cerebral disease such as Alzheimer's disease. Lesions that affect the inferomedial part of the temporo-occipital region tend to cause an inability to recognize facial features (pl:osopagnosia), while lesions of either parietal lobe rnay produce astereognosis, in which patients fail to recognize the forms of objects when felt but not when viewed (Brazis, pp. 481-508).

Answer 46

**C. Ventral motoneuron ** ## Footnote The muscle stretch reflex is a monosynaptic circuit that is dependent on two neurons. Afferent axons serving the muscle stretch reflex synapse directly with ventralmotoneurons (Carpenter, p. 79).

Answer 47

**A. 1,2, and 3 are correct** ## Footnote After a complete spinal cord injury, all voluntary movements and sensation below the level of the lesion are lost, but a number of visceral reflexes may be preserved in some cases. A patient with a complete C2 spinal cord injury is unlikely to be able to breathe, since the spinal cord does not contain intrinsic circuitry for breathing. Retained reflexes may include micturition, defecation, peristalsis, and possibly even ejaculation, although there may be no sensation of the sexual act (Brazis, pp. 85- 88; DeMyer, pp. 142- 143).

Answer 48

**A. 1,2, and 3 ** ## Footnote The most important cranial nerve for palatal elevation is generally CN X. Interruption of the left CN X can cause paralysis of palatal elevation on the left side. Taste, swallowing, and phonation are also partially subserved by CN Xi therefore an insult to this cranial nerve may result in problems with speech, swallowing, and taste. Salivation problems may be evident with deficits in CN VII and IX (Carpenter, pp.137-144,172-173).

Answer 49

I ## Footnote The major ascending tracts of the spinal cord (left) are the dorsal columns, spinothalamic tract, dOl'sal spinocerebellar tract, and ventral spinocerebellar tract. The dOl'sal columns convey tactile discrimination (Meissner corpuscles), vibration (pacinian corpuscle), joint position sense (muscle spindles and Golgi tendon organs), and conscious proprioception. First-order neurons give rise to axons that ascend in the fasciculus cuneatus (A, upper extremity fibers) and gracilis (E, lower extremity), which terminate in the gracile and cuneate nuclei of the medulla. Second-order neurons, known as arcuate fibers, cross to the contralateral side as the medial lemniscus and ascend to the ventral posterolateral (VPL) nucleus of the thalamus. Synaptic connections are then made in the thalamus with third-order neurons, which travel through the posterior limb of the internal capsule to reach the postcentral gyrus of the cerebral cortex.

Answer 50

J ## Footnote The major ascending tracts of the spinal cord (left) are the dorsal columns, spinothalamic tract, dOl'sal spinocerebellar tract, and ventral spinocerebellar tract. The dOl'sal columns convey tactile discrimination (Meissner corpuscles), vibration (pacinian corpuscle), joint position sense (muscle spindles and Golgi tendon organs), and conscious proprioception. First-order neurons give rise to axons that ascend in the fasciculus cuneatus (A, upper extremity fibers) and gracilis (E, lower extremity), which terminate in the gracile and cuneate nuclei of the medulla. Second-order neurons, known as arcuate fibers, cross to the contralateral side as the medial lemniscus and ascend to the ventral posterolateral (VPL) nucleus of the thalamus. Synaptic connections are then made in the thalamus with third-order neurons, which travel through the posterior limb of the internal capsule to reach the postcentral gyrus of the cerebral cortex.

Answer 51

F ## Footnote The major ascending tracts of the spinal cord (left) are the dorsal columns, spinothalamic tract, dOl'sal spinocerebellar tract, and ventral spinocerebellar tract. The dOl'sal columns convey tactile discrimination (Meissner corpuscles), vibration (pacinian corpuscle), joint position sense (muscle spindles and Golgi tendon organs), and conscious proprioception. First-order neurons give rise to axons that ascend in the fasciculus cuneatus (A, upper extremity fibers) and gracilis (E, lower extremity), which terminate in the gracile and cuneate nuclei of the medulla. Second-order neurons, known as arcuate fibers, cross to the contralateral side as the medial lemniscus and ascend to the ventral posterolateral (VPL) nucleus of the thalamus. Synaptic connections are then made in the thalamus with third-order neurons, which travel through the posterior limb of the internal capsule to reach the postcentral gyrus of the cerebral cortex.

Answer 52

B ## Footnote The major ascending tracts of the spinal cord (left) are the dorsal columns, spinothalamic tract, dOl'sal spinocerebellar tract, and ventral spinocerebellar tract. The dOl'sal columns convey tactile discrimination (Meissner corpuscles), vibration (pacinian corpuscle), joint position sense (muscle spindles and Golgi tendon organs), and conscious proprioception. First-order neurons give rise to axons that ascend in the fasciculus cuneatus (A, upper extremity fibers) and gracilis (E, lower extremity), which terminate in the gracile and cuneate nuclei of the medulla. Second-order neurons, known as arcuate fibers, cross to the contralateral side as the medial lemniscus and ascend to the ventral posterolateral (VPL) nucleus of the thalamus. Synaptic connections are then made in the thalamus with third-order neurons, which travel through the posterior limb of the internal capsule to reach the postcentral gyrus of the cerebral cortex.

Answer 53

G ## Footnote The major ascending tracts of the spinal cord (left) are the dorsal columns, spinothalamic tract, dOl'sal spinocerebellar tract, and ventral spinocerebellar tract. The dOl'sal columns convey tactile discrimination (Meissner corpuscles), vibration (pacinian corpuscle), joint position sense (muscle spindles and Golgi tendon organs), and conscious proprioception. First-order neurons give rise to axons that ascend in the fasciculus cuneatus (A, upper extremity fibers) and gracilis (E, lower extremity), which terminate in the gracile and cuneate nuclei of the medulla. Second-order neurons, known as arcuate fibers, cross to the contralateral side as the medial lemniscus and ascend to the ventral posterolateral (VPL) nucleus of the thalamus. Synaptic connections are then made in the thalamus with third-order neurons, which travel through the posterior limb of the internal capsule to reach the postcentral gyrus of the cerebral cortex.

Answer 54

C ## Footnote The major ascending tracts of the spinal cord (left) are the dorsal columns, spinothalamic tract, dOl'sal spinocerebellar tract, and ventral spinocerebellar tract. The dOl'sal columns convey tactile discrimination (Meissner corpuscles), vibration (pacinian corpuscle), joint position sense (muscle spindles and Golgi tendon organs), and conscious proprioception. First-order neurons give rise to axons that ascend in the fasciculus cuneatus (A, upper extremity fibers) and gracilis (E, lower extremity), which terminate in the gracile and cuneate nuclei of the medulla. Second-order neurons, known as arcuate fibers, cross to the contralateral side as the medial lemniscus and ascend to the ventral posterolateral (VPL) nucleus of the thalamus. Synaptic connections are then made in the thalamus with third-order neurons, which travel through the posterior limb of the internal capsule to reach the postcentral gyrus of the cerebral cortex.

Answer 55

I ## Footnote The major ascending tracts of the spinal cord (left) are the dorsal columns, spinothalamic tract, dOl'sal spinocerebellar tract, and ventral spinocerebellar tract. The dOl'sal columns convey tactile discrimination (Meissner corpuscles), vibration (pacinian corpuscle), joint position sense (muscle spindles and Golgi tendon organs), and conscious proprioception. First-order neurons give rise to axons that ascend in the fasciculus cuneatus (A, upper extremity fibers) and gracilis (E, lower extremity), which terminate in the gracile and cuneate nuclei of the medulla. Second-order neurons, known as arcuate fibers, cross to the contralateral side as the medial lemniscus and ascend to the ventral posterolateral (VPL) nucleus of the thalamus. Synaptic connections are then made in the thalamus with third-order neurons, which travel through the posterior limb of the internal capsule to reach the postcentral gyrus of the cerebral cortex.

Answer 56

H ## Footnote The major ascending tracts of the spinal cord (left) are the dorsal columns, spinothalamic tract, dOl'sal spinocerebellar tract, and ventral spinocerebellar tract. The dOl'sal columns convey tactile discrimination (Meissner corpuscles), vibration (pacinian corpuscle), joint position sense (muscle spindles and Golgi tendon organs), and conscious proprioception. First-order neurons give rise to axons that ascend in the fasciculus cuneatus (A, upper extremity fibers) and gracilis (E, lower extremity), which terminate in the gracile and cuneate nuclei of the medulla. Second-order neurons, known as arcuate fibers, cross to the contralateral side as the medial lemniscus and ascend to the ventral posterolateral (VPL) nucleus of the thalamus. Synaptic connections are then made in the thalamus with third-order neurons, which travel through the posterior limb of the internal capsule to reach the postcentral gyrus of the cerebral cortex.

Answer 57

**B. Anterior, followed by superior, inferior, and posterior ** ## Footnote Facial nerve displacement by an acoustic neuroma is most commonly (in deCI'easing order of frequency) anterior, followed by superior, inferior, and posterior. The facial nerve is often stretched during microdissection and is most susceptible to injury at the proximal rim of the porus acusticus (Connolly, p. 475)

Answer 58

**C. Conus medullaris syndrome ** ## Footnote Paralysis of pelvic floor muscles, early sphincter and bladder dysfunction, symmetric saddle anestheSia, impaired erection and ejaculation, constipation, and minimal pain best characterize the conus medullaris syndrome. A tethered cord may present with a combination of neurologic, urologic , orthopediC, and dermatologic manifestations. Commonly patients present with numb feet, muscle atrophy, upper motor neuron Signs, bowel and bladder dysfunction, foot deformities, scoliOSiS, and cutaneous stigmata of spinal dysraphism. Compression of the lumbar and sacral roots below L3 often results in cauda equina syndrome, which is characterized by early pain, asymmetric saddle anesthesia, and a variable patellar reflex response . Sphincter changes are often similar to those of the conus medullaris syndrome but tend to occur late in the clinical course. With Sllesions, there is weakness of the triceps surae, flexor digitorum longus (FDL), flexor hallucis longus (FHL), and small foot muscles. The Achilles reflexes are absent, whereas the patellar reflexes are preserved. There is complete sensory loss over the sole, heel, and outer part of the foot and ankle . The gastrocnemius and soleus muscles are stronger with S2 segmental lesions, however, the FDL, FHL, and foot muscles remain weak. The sensory loss tends to involve the upper part of the dOl'sal calf, dorsolateral thigh, and the saddle area (Brazis, pp. 99-100)

Answer 59

**D. Trauma ** ## Footnote This CT demonstrates a subarachnoid hemorrhage (SAH), which is most commonly seen after trauma. Although the blood pattern may vary, traumatic SAH often involves the convexities of the cerebral hemispheres, while aneurysmal subarachnoid hemorrhages generally have a preponderance of blood in the basal cisterns (Greenberg, p. 754)

Answer 60

**D. Orbitofrontal cortex** ## Footnote Experimental studies indicate the orbitofrontal cortex is a key region involved with the conscious perception of smell, as lesions in this region have been shown to result in failure to discriminate between various odorants (Kandel, p.633).

Answer 61

**D. Lhermitte-Duclos disease** ## Footnote This T2-weighted image shows the hyperintense and thickened folia in a characteristic laminated pattern that is most consistent with Lhermitte-Duclos disease. It is associated with hypertrophy of granular cell neurons and axonal hypennyelination in the molecular layer (Osborn ON, pp.69-70).

Answer 62

**C. Hypertrophy of granular-cell neurons and axonal hypermyelination in the molecular layer ** ## Footnote This T2-weighted image shows the hyperintense and thickened folia in a characteristic laminated pattern that is most consistent with Lhermitte-Duclos disease. It is associated with hypertrophy of granular cell neurons and axonal hypennyelination in the molecular layer (Osborn ON, pp.69-70).

Answer 63

**D. Aneurysm ** ## Footnote This T2-weighted MRI shows a right temporal lobe mass with signal loss (flow void), which is most consistent with a large middle cerebral artery anemysm (Osborn ON, pp. 266- 268)

Answer 64

**C. Seesaw nystagmus **

Answer 65

**G. Convergence-retraction nystagmus **

Answer 66

**I. Abducting nystagmus **

Answer 67

**E. Ocular bobbing **

Answer 68

**H. Ocular myoclonus**

Answer 69

**B. Upbeat nystagmus **

Answer 70

**A. Downbeat nystagmus **

Answer 71

**J. Bruns nystagmus **

Answer 72

**A. Right superior oblique ** ## Footnote Orbital injuries often impair the action of the superior oblique muscle because of displacement of the trochlea, which attaches to the anterior rim of the orbit and acts as a sling for the recurrent course of the trochlear tendon. Looking down and to the left typically involves the right superior oblique (trochlear nerve , IV) and left inferior rectus (oculomotor nerve , III) muscles. \Vhen the eyes look conjuga tely toward any object, the muscle that is the prime mover works in unison with the muscle of the opposite eye (Kline, pp. 105- 114).

Answer 73

**E. Tumor suppressor gene that maps to chromosome 9p25 ** ## Footnote Note the numerous capillaries and cells with a vacuolated appearance in this photomicrograph depicting a hemangioblastoma. This tumor is associated with VI-IL in about 25% of cases, is carried in an autosomal dominant fashion (chromosome 3p25), and is associated with retinal angioma, renal cell carcinoma, renal and pancreatic cysts, pheochromocytoma, or epididymal papillary cystadenoma . This tumor may cause polycythemia in about 10% of cases due to inappropriate production of erythropoietin (Ellison, pp. 736- 738).

Answer 74

**B. ABO incompatibility ** ## Footnote Acute hemolytic transfusion reactions are uncommon and are rarely life-threatening. They are produced by antibodies in the recipient that bind to ABO surface antigens or erythrocytes of mismatched donor blood. These antibodies /L\: complement and can produce rapid cell lysis within minutes. Lysis then provokes a severe inflammatory reaction, which can lead to hypotension, multiorgan dysfunction, and a host of other clinical findings. This type of transfusion reaction is often the result of identification errors, leading to ABO mismatched blood . The transfusion should be stopped immediately; the volume status, urine output, and blood pressure should be monitored and maintained; and the patient's blood sent for free hemoglobin, haptoglobin levels, and a Coombs' test. Treatment includes supportive care with maintenance of good urine out.

Answer 75

**D. The transfusion should be stopped and the patient's blood sent for free hemoglobin, haptoglobin levels, and Coombs' test ** ## Footnote Acute hemolytic transfusion reactions are uncommon and are rarely life-threatening. They are produced by antibodies in the recipient that bind to ABO surface antigens or erythrocytes of mismatched donor blood. These antibodies /L\: complement and can produce rapid cell lysis within minutes. Lysis then provokes a severe inflammatory reaction, which can lead to hypotension, multiorgan dysfunction, and a host of other clinical findings. This type of transfusion reaction is often the result of identification errors, leading to ABO mismatched blood . The transfusion should be stopped immediately; the volume status, urine output, and blood pressure should be monitored and maintained; and the patient's blood sent for free hemoglobin, haptoglobin levels, and a Coombs' test. Treatment includes supportive care with maintenance of good urine out.

Answer 76

**E. Ependymoma** ## Footnote The presence of l11ultiple intradural spinal cord tumors is relatively common with NF-2 and may include ependymomas (most common), schwannomas, and meningiomas (Greenberg, p. 478).

Answer 77

**A. Subiculum and entorhinal cortex** ## Footnote The pyramidal neurons of the hippocampus (Aml11on's horn) send numerous fiber projections to the subiculuIll and entorhinal cortex (area 28), which form the anterior part of the parahippocampal gyrus (Carpenter, pp. 369- 382).

Answer 78

**A. Hemangiopericytoma ** ## Footnote Note the "staghorn" vascular channel in this grade II hemangiopericytoma. These tumors are vimentin-positive , ENlA-negative, have a dense arrangement of sheet-like cells, and have a high nuclear-cytoplasmic ratio. Other characteristics include focallobularity, paucicellular areas, and dense periceIJular reticulin (Ellison, pp. 736- 738).

Answer 79

**C. Expressive aphasia ** ## Footnote Lesions that occupy the anterior part of the left parasylvian fissure may cause a nontluent type of aphasia (Broca's). This region may abut the parts of the motor cortex that supply the upper motor neuron fibers for the contralateral facial nucleus. Therefore a patient with right-sided upper motor neuron facial deficit may also have an expressive-type of aphasia originating from Broca's area (Brazis, pp. 511- 516)

Answer 80

**B. Globus pallidus ** ## Footnote A coronal section through the genu of the internal capsule would almost exclusively bisect the globus pallid us, which is triangle-shaped, with its apex fitting into the genu of the intcrnal capsule (Carpenter, pp. 337- 344).

Answer 81

**C. Anterior temporal artery ** ## Footnote The middle cerebral artery (MCA) is divided anatomically into four major segments: M1 (horizontal) segment, M2 (insular segment), M3 (opercular segment), and M4 (cortical) segment. The anterior temporal artery typically arises from the 1-11 segment of the MCA before the bifurcation. It passes directly anteriorly and inferiorly over the temporal tip and usually does not course toward the sylvian fissure. Although relatively uncommon, aneurysms can form at the origin or further distally along this vessel (as depicted here). An accessory middle cerebral artery is an MCA branch that arises from either the ACA (more common) or the ICA and parallels the M1 segment toward the sylvian fissure. The lenticulostriate arteries are divided into a smaller medial group and a larger lateral group that originate from the distal half of the M1 segment and project superiorly to enter the anterior perforated substance to supply parts of the lentiform nuclei, caudate nucleus, and internal capsule. The posterior temporal artery usually originates from the M4 segment of the MCA and supplies the posterior temporal lobe. The frontopolar artery is a branch of the anterior cerebral artery (A2 portion), which originates below the rostrum or genu of the corpus callosum and extends anteriorly to supply the frontal pole (Osborn DCA, pp. 135- 137).

Answer 82

**C. 70% ** ## Footnote Most patients develop some degree of vessel narrowing after aneurysmal subarachnoid hemorrhage. About 70% will develop angiographic vasospasm, and approximately 30% will go on to develop symptomatic vasospasm (Youmans, p.1545).

Answer 83

**E. Aand C** ## Footnote Over the past few decades a variety of medical, surgical, and radiation interventions have evolved that have proven effective in reducing GH levels. No one treatment is uniformly effective, and often a combination of interventions is required. \\Then a macroadenoma is surgically resected transsphenoidally, endocrine remission rates vary between 65 and 90%. When a macroadenoma is resected, immediate postoperative remission is reported to be even lower (30 and 79%). The rate of remission is adversely affected by a higher preoperative GH level and larger invasive tumors. Therefore biochemical cure with surgery for large GH-secreting macroadenomas is typically not expected. Conventional radiation therapy can usually shrinl, pituitary tumors when up to 50 Gy is delivered in 1.8-Gy fractions over 6 weeks, but a decrease or normalization of GIl levels usually takes many years. When initial GI-I levels are> 100 pg/mL, only 60% of patients will attain GH levels < 5 ~lg/mL after 18 years following radiation, and about 50% will develop hypopituitarism within 10 years. Radiosurgery has the same disadvantages as conventional radiation and would add increased risk in this patient due to the proximity of the lesion to the optic nerves and chiasm. Although perhaps controversial, some endocrinologists are advocating primary drug therapy in patients with GI-I-secreting macroadenomas (especially with normal vision). Bromocriptine, a dopamine agonist, has been documented to lower GH levels in up to 71% of patients, and octreotide, a somatostatin analogue, has achieved similar results. If there is no shrinkage of the tumor after 16 weeks of therapy, further use of medication has been shown to have little impact. Patients with rapidly deteriorating vision or other neurologic problems related to the lesion (unlike our patient) are often not good candidates for a trial of medical therapy and often require more urgent surgical intervention. Nevertheless, the most effective treatment strategy for acromegaly secondary to a GIl-secreting macroadenoma usually requires a combination of surgical and medical options (Berger, pp. 405- 406).

Answer 84

A ## Footnote Figure 8.108-8.116Q demonstrates the surgical anatomy of the right lateral and anterior third ventricle during endoscopic third ventriculostomy for aqueductal stenosis. The ventriculostomy site is depicted in the floor of the third ventricle in this figure. The veins of the third ventricular system collect into deeper veins that course in a subependymal location as they travel through the margins of the choroidal fissure to empty into the internal cerebral, basal, and great veins. In general, the veins draining the frontal horn and body of the third ventricle drain into the internal cerebral vein (not depicted here) as it courses through the velum interpositum; those draining the temporal horn drain into a segment of the basal vein of Rosenthal coursing through the ambient cistern; and the veins from the atrium drain into segments of the basal, internal cerebral, and great veins coursing through the quadrigeminal cistern. Of note , the thalamostriate vein passes forward in the sulcus between the caudate nucleus and thalamus toward the foramen of Monro (FOM), where it turns sharply posterior to enter the velum interpositum to join the internal cerebral vein. The angle formed by the junction of the internal cerebral vein and thalamostriate vein, referred to as the venous angle, approximates the level of the FOM 011 the lateral view of a cerebral angiogram (Will~ins, pp. 1427-1429; Youmans, pp. 1237- 1240).

Answer 85

D ## Footnote Figure 8.108-8.116Q demonstrates the surgical anatomy of the right lateral and anterior third ventricle during endoscopic third ventriculostomy for aqueductal stenosis. The ventriculostomy site is depicted in the floor of the third ventricle in this figure. The veins of the third ventricular system collect into deeper veins that course in a subependymal location as they travel through the margins of the choroidal fissure to empty into the internal cerebral, basal, and great veins. In general, the veins draining the frontal horn and body of the third ventricle drain into the internal cerebral vein (not depicted here) as it courses through the velum interpositum; those draining the temporal horn drain into a segment of the basal vein of Rosenthal coursing through the ambient cistern; and the veins from the atrium drain into segments of the basal, internal cerebral, and great veins coursing through the quadrigeminal cistern. Of note , the thalamostriate vein passes forward in the sulcus between the caudate nucleus and thalamus toward the foramen of Monro (FOM), where it turns sharply posterior to enter the velum interpositum to join the internal cerebral vein. The angle formed by the junction of the internal cerebral vein and thalamostriate vein, referred to as the venous angle, approximates the level of the FOM 011 the lateral view of a cerebral angiogram (Will~ins, pp. 1427-1429; Youmans, pp. 1237- 1240).

Answer 86

G ## Footnote Figure 8.108-8.116Q demonstrates the surgical anatomy of the right lateral and anterior third ventricle during endoscopic third ventriculostomy for aqueductal stenosis. The ventriculostomy site is depicted in the floor of the third ventricle in this figure. The veins of the third ventricular system collect into deeper veins that course in a subependymal location as they travel through the margins of the choroidal fissure to empty into the internal cerebral, basal, and great veins. In general, the veins draining the frontal horn and body of the third ventricle drain into the internal cerebral vein (not depicted here) as it courses through the velum interpositum; those draining the temporal horn drain into a segment of the basal vein of Rosenthal coursing through the ambient cistern; and the veins from the atrium drain into segments of the basal, internal cerebral, and great veins coursing through the quadrigeminal cistern. Of note , the thalamostriate vein passes forward in the sulcus between the caudate nucleus and thalamus toward the foramen of Monro (FOM), where it turns sharply posterior to enter the velum interpositum to join the internal cerebral vein. The angle formed by the junction of the internal cerebral vein and thalamostriate vein, referred to as the venous angle, approximates the level of the FOM 011 the lateral view of a cerebral angiogram (Will~ins, pp. 1427-1429; Youmans, pp. 1237- 1240).

Answer 87

B ## Footnote Figure 8.108-8.116Q demonstrates the surgical anatomy of the right lateral and anterior third ventricle during endoscopic third ventriculostomy for aqueductal stenosis. The ventriculostomy site is depicted in the floor of the third ventricle in this figure. The veins of the third ventricular system collect into deeper veins that course in a subependymal location as they travel through the margins of the choroidal fissure to empty into the internal cerebral, basal, and great veins. In general, the veins draining the frontal horn and body of the third ventricle drain into the internal cerebral vein (not depicted here) as it courses through the velum interpositum; those draining the temporal horn drain into a segment of the basal vein of Rosenthal coursing through the ambient cistern; and the veins from the atrium drain into segments of the basal, internal cerebral, and great veins coursing through the quadrigeminal cistern. Of note , the thalamostriate vein passes forward in the sulcus between the caudate nucleus and thalamus toward the foramen of Monro (FOM), where it turns sharply posterior to enter the velum interpositum to join the internal cerebral vein. The angle formed by the junction of the internal cerebral vein and thalamostriate vein, referred to as the venous angle, approximates the level of the FOM 011 the lateral view of a cerebral angiogram (Will~ins, pp. 1427-1429; Youmans, pp. 1237- 1240).

Answer 88

F ## Footnote Figure 8.108-8.116Q demonstrates the surgical anatomy of the right lateral and anterior third ventricle during endoscopic third ventriculostomy for aqueductal stenosis. The ventriculostomy site is depicted in the floor of the third ventricle in this figure. The veins of the third ventricular system collect into deeper veins that course in a subependymal location as they travel through the margins of the choroidal fissure to empty into the internal cerebral, basal, and great veins. In general, the veins draining the frontal horn and body of the third ventricle drain into the internal cerebral vein (not depicted here) as it courses through the velum interpositum; those draining the temporal horn drain into a segment of the basal vein of Rosenthal coursing through the ambient cistern; and the veins from the atrium drain into segments of the basal, internal cerebral, and great veins coursing through the quadrigeminal cistern. Of note , the thalamostriate vein passes forward in the sulcus between the caudate nucleus and thalamus toward the foramen of Monro (FOM), where it turns sharply posterior to enter the velum interpositum to join the internal cerebral vein. The angle formed by the junction of the internal cerebral vein and thalamostriate vein, referred to as the venous angle, approximates the level of the FOM 011 the lateral view of a cerebral angiogram (Will~ins, pp. 1427-1429; Youmans, pp. 1237- 1240).

Answer 89

C ## Footnote Figure 8.108-8.116Q demonstrates the surgical anatomy of the right lateral and anterior third ventricle during endoscopic third ventriculostomy for aqueductal stenosis. The ventriculostomy site is depicted in the floor of the third ventricle in this figure. The veins of the third ventricular system collect into deeper veins that course in a subependymal location as they travel through the margins of the choroidal fissure to empty into the internal cerebral, basal, and great veins. In general, the veins draining the frontal horn and body of the third ventricle drain into the internal cerebral vein (not depicted here) as it courses through the velum interpositum; those draining the temporal horn drain into a segment of the basal vein of Rosenthal coursing through the ambient cistern; and the veins from the atrium drain into segments of the basal, internal cerebral, and great veins coursing through the quadrigeminal cistern. Of note , the thalamostriate vein passes forward in the sulcus between the caudate nucleus and thalamus toward the foramen of Monro (FOM), where it turns sharply posterior to enter the velum interpositum to join the internal cerebral vein. The angle formed by the junction of the internal cerebral vein and thalamostriate vein, referred to as the venous angle, approximates the level of the FOM 011 the lateral view of a cerebral angiogram (Will~ins, pp. 1427-1429; Youmans, pp. 1237- 1240).

Answer 90

E ## Footnote Figure 8.108-8.116Q demonstrates the surgical anatomy of the right lateral and anterior third ventricle during endoscopic third ventriculostomy for aqueductal stenosis. The ventriculostomy site is depicted in the floor of the third ventricle in this figure. The veins of the third ventricular system collect into deeper veins that course in a subependymal location as they travel through the margins of the choroidal fissure to empty into the internal cerebral, basal, and great veins. In general, the veins draining the frontal horn and body of the third ventricle drain into the internal cerebral vein (not depicted here) as it courses through the velum interpositum; those draining the temporal horn drain into a segment of the basal vein of Rosenthal coursing through the ambient cistern; and the veins from the atrium drain into segments of the basal, internal cerebral, and great veins coursing through the quadrigeminal cistern. Of note , the thalamostriate vein passes forward in the sulcus between the caudate nucleus and thalamus toward the foramen of Monro (FOM), where it turns sharply posterior to enter the velum interpositum to join the internal cerebral vein. The angle formed by the junction of the internal cerebral vein and thalamostriate vein, referred to as the venous angle, approximates the level of the FOM 011 the lateral view of a cerebral angiogram (Will~ins, pp. 1427-1429; Youmans, pp. 1237- 1240).

Answer 91

H ## Footnote Figure 8.108-8.116Q demonstrates the surgical anatomy of the right lateral and anterior third ventricle during endoscopic third ventriculostomy for aqueductal stenosis. The ventriculostomy site is depicted in the floor of the third ventricle in this figure. The veins of the third ventricular system collect into deeper veins that course in a subependymal location as they travel through the margins of the choroidal fissure to empty into the internal cerebral, basal, and great veins. In general, the veins draining the frontal horn and body of the third ventricle drain into the internal cerebral vein (not depicted here) as it courses through the velum interpositum; those draining the temporal horn drain into a segment of the basal vein of Rosenthal coursing through the ambient cistern; and the veins from the atrium drain into segments of the basal, internal cerebral, and great veins coursing through the quadrigeminal cistern. Of note , the thalamostriate vein passes forward in the sulcus between the caudate nucleus and thalamus toward the foramen of Monro (FOM), where it turns sharply posterior to enter the velum interpositum to join the internal cerebral vein. The angle formed by the junction of the internal cerebral vein and thalamostriate vein, referred to as the venous angle, approximates the level of the FOM 011 the lateral view of a cerebral angiogram (Will~ins, pp. 1427-1429; Youmans, pp. 1237- 1240).

Answer 92

I ## Footnote Figure 8.108-8.116Q demonstrates the surgical anatomy of the right lateral and anterior third ventricle during endoscopic third ventriculostomy for aqueductal stenosis. The ventriculostomy site is depicted in the floor of the third ventricle in this figure. The veins of the third ventricular system collect into deeper veins that course in a subependymal location as they travel through the margins of the choroidal fissure to empty into the internal cerebral, basal, and great veins. In general, the veins draining the frontal horn and body of the third ventricle drain into the internal cerebral vein (not depicted here) as it courses through the velum interpositum; those draining the temporal horn drain into a segment of the basal vein of Rosenthal coursing through the ambient cistern; and the veins from the atrium drain into segments of the basal, internal cerebral, and great veins coursing through the quadrigeminal cistern. Of note , the thalamostriate vein passes forward in the sulcus between the caudate nucleus and thalamus toward the foramen of Monro (FOM), where it turns sharply posterior to enter the velum interpositum to join the internal cerebral vein. The angle formed by the junction of the internal cerebral vein and thalamostriate vein, referred to as the venous angle, approximates the level of the FOM 011 the lateral view of a cerebral angiogram (Will~ins, pp. 1427-1429; Youmans, pp. 1237- 1240).

Answer 93

**E. All of the above** ## Footnote Occlusion or injury of the thalamostriate vein may cause drowsiness, hemiplegia, mutism, and hemorrhagic infarction of the basal ganglia (Will~ins, pp. 1427-1429).

Answer 94

**C. 2 and 4 are correct ** ## Footnote Acute microscopic changes after DAI typically include axonal retraction balls and perivascular hemorrhages, while in later stages there can be astrogliosis, endothelial proliferation, and accumulation of hemosiderin-laden macrophages (Marion, pp. 40-45; Ellison, pp. 249- 257; Ramsey, pp. 431- 434).

Answer 95

**C. 7 to B cm ** ## Footnote In approaching the posterior ilium during autogenous iliac bone graft harvesting, a limited incision that stays within 8 cm of the posterior superior iliac spine typically avoids the superior cluneal nerves. Dissection is then carried down to the gluteal fascia, which should be opened directly above the iliac crest to facilitate fascial closure. During subcrestal exposure, the lateral subperiosteal dissection should be carried to the gluteus medius and tensor fascia lata muscles. Subperiosteal dissection usually avoids damage to the superior gluteal artery, which courses through the musculature. The sciatic notch usually lies approximately 7 to 8 cm below the iliac crest and must not be violated, as it harbors the main trunk of the sciatic artery, the sciatic nerve , and the ureter, which runs ventral to the superior gluteal artery. j'dedially, the dissection should extend to the iliacus muscle , which prevents injury to the iliohypogastric and ilioinguinal nerves (Connolly, pp. 819- 820)

Answer 96

**D. Developmental ** ## Footnote Note the absence of the corpus callosum and the high-riding third ventricle on this sagittal MRI depicting agenesis of the corpus callosum. This condition is usually not associated with Chiari I malformation but rather with the Chiari II malformation (Osborn DN, pp.29- 33).

Answer 97

**D. Agenesis of the corpus callosum** ## Footnote Note the absence of the corpus callosum and the high-riding third ventricle on this sagittal MRI depicting agenesis of the corpus callosum. This condition is usually not associated with Chiari I malformation but rather with the Chiari II malformation (Osborn DN, pp.29- 33).

Answer 98

**B. Chiari I malformation ** ## Footnote Note the absence of the corpus callosum and the high-riding third ventricle on this sagittal MRI depicting agenesis of the corpus callosum. This condition is usually not associated with Chiari I malformation but rather with the Chiari II malformation (Osborn DN, pp.29- 33).

Answer 99

**B. 1 and 3 are correct ** ## Footnote Stability at the atlantoaxial unit is mainly proVided by the horizontal portion of the cruciate ligament (transverse atlantal ligament), and the paired alar ligaments (atlantoalar portion) that connect the dens with the lateral masses of CI. With disruption of these ligaments, the remaining cruciate and apical ligaments are insufficient to maintain stability. Ligaments that connect the a.us to the occiput include the tectorial membrane (rostral continuation of the posterior longitudinal ligament), occipitoalar portion of the alar ligament, and the apical ligament (connects the tip of dens to the foramen magnum), while the ligaments connecting the atlas to the occiput include the tectorial membrane and anterior longitudinal ligament (Greenberg, p. 701; Youmans, pp. 3528-3551).

Answer 100

**C. Glomus jugulare tumor ** ## Footnote This patient harbors a glomus jugulare tumor, which often presents with unilate ral hearing loss or pulsatile tinnitus. Intracranial extension usually affects multiple cranial nerves, which may result in a number of clinical problems including dysphagia . Angiography is essential because it helps with surgical planning. It helps delineate the blood supply to the tumor as well as collateral blood flow to the brain. Often preoperative embolization is a useful adjunct for these highly vascular and locally invasive tumors. Although observation with serial imaging studies to determine tumor progression may be an appropriate option for medically frail patients, gross total resection is considered the trea tment of choice for symptomatic lesions (Youmans, pp.1295-1308).

Answer 101

**D. Attempted gross total resec tion ** ## Footnote This patient harbors a glomus jugulare tumor, which often presents with unilate ral hearing loss or pulsatile tinnitus. Intracranial extension usually affects multiple cranial nerves, which may result in a number of clinical problems including dysphagia . Angiography is essential because it helps with surgical planning. It helps delineate the blood supply to the tumor as well as collateral blood flow to the brain. Often preoperative embolization is a useful adjunct for these highly vascular and locally invasive tumors. Although observation with serial imaging studies to determine tumor progression may be an appropriate option for medically frail patients, gross total resection is considered the trea tment of choice for symptomatic lesions (Youmans, pp.1295-1308).

Answer 102

**A. Direct axial load on a neutral neck ** ## Footnote The fracture-pattern (Jefferson fracture) depicted on this axial CT scan most often results from an axial load on a neutral neck. These patients are usually neurologically intact due to the large diameter of the spinal canal at this level. If the sum of overhang of both lateral masses on C2 is :2: 7 mm, the transverse ligament is probably disrupted, which requires rigid immobilization (usually with a halo vest) or surgical n.xation if additional fractures are present (Greenberg, pp. 702-703).

Answer 103

**D. 7 nUll ** ## Footnote The fracture-pattern (Jefferson fracture) depicted on this axial CT scan most often results from an axial load on a neutral neck. These patients are usually neurologically intact due to the large diameter of the spinal canal at this level. If the sum of overhang of both lateral masses on C2 is :2: 7 mm, the transverse ligament is probably disrupted, which requires rigid immobilization (usually with a halo vest) or surgical n.xation if additional fractures are present (Greenberg, pp. 702-703).

Answer 104

**E. Impaired lacrimation** ## Footnote A lesion of the facial nerve distal to the geniculate ganglion but proximal to the stylomastOid foramen typically results in complete paralysis of all ipsilateral fmuscles, a diminished corneal reflex (with preserved corneal sensation, CN V) , impaired sublingual and submandibular salivary gland secretions, hyperacusis, and frequently loss of taste in the anterior two-thirds of the tongue ipsilaterally. Hyperacusis results from paralysis of the stapedius muscle, while salivary secretions are impaired due to the interruption of preganglionic parasympathetic fibers. Lesions proximal to the geniculate ganglion produce all of the disturbances described above and invariably loss of taste in the anterior two-thirds of the tongue and decreased lacrimation. This lesion interrupts all SVA fibers that course centrally and all preganglionic (GVE) fibers as they pass to the pterygopalatine and submandibular ganglia . Taste is permanently lost and no regeneration of sensory fibers takes place. Preganglionic parasympathetic fibers may regenerate , but this may occur in an aberrant fashion. Fibers that previously projected to the submandibular ganglion may regrow and enter the greater petrosal nerve, which may result in lacrimation after a salivary stimulus ("crocodile tears") (Carpenter, pp. 172-173).

Answer 105

**A. Parasympathetic fibers that previously projected to the submandibular ganglion may regrow and ente r the greater petrosal nerve** ## Footnote A lesion of the facial nerve distal to the geniculate ganglion but proximal to the stylomastOid foramen typically results in complete paralysis of all ipsilateral fmuscles, a diminished corneal reflex (with preserved corneal sensation, CN V) , impaired sublingual and submandibular salivary gland secretions, hyperacusis, and frequently loss of taste in the anterior two-thirds of the tongue ipsilaterally. Hyperacusis results from paralysis of the stapedius muscle, while salivary secretions are impaired due to the interruption of preganglionic parasympathetic fibers. Lesions proximal to the geniculate ganglion produce all of the disturbances described above and invariably loss of taste in the anterior two-thirds of the tongue and decreased lacrimation. This lesion interrupts all SVA fibers that course centrally and all preganglionic (GVE) fibers as they pass to the pterygopalatine and submandibular ganglia . Taste is permanently lost and no regeneration of sensory fibers takes place. Preganglionic parasympathetic fibers may regenerate , but this may occur in an aberrant fashion. Fibers that previously projected to the submandibular ganglion may regrow and enter the greater petrosal nerve, which may result in lacrimation after a salivary stimulus ("crocodile tears") (Carpenter, pp. 172-173).

Answer 106

**B. Anterior thalamic nucleus ** ## Footnote B. ~l'fanllllillary fibers projecting from the medialmammillary nucleus and, to a lesser extent, intermediate and lateral mammillary nuclei form a fiber bundle called the fasciculus mammillaris princes, which divides into two components: the mammillothalamic tract and mammillotegmental tract. The mammillothalamic tract contains fibers that originate from tbe medial mamnlillary nucleus and project to the anterior thalamic nucleus. Fibers from the hippocampus are also superimposed on this fiber bundle as they travel to the anterior thalamic nucleus through the fornLx. The mammillotegmental tract terminates in the dorsal and ventral tegmental nuclei (Carpenter, p. 309).

Answer 107

**B. Uncinate fasciculus (of Russell) ** ## Footnote Crossed fibers from the fastigial nucleus emerge from the cerebellum through the uncinate fasciculus of Russell, which arches around the superior cerebellar peduncle. Uncrossed fastigial efferents project to the brainstem in the juxtarestifonn body. The largest number of fastigial efferents project to structures in the lower brainstem (nucleus reticularis gigantocellularis, central pontine reticular formation, dorsal paramedian reticular nucleus). A small number of fibers ascend in the dorsolateral brainstem and send collaterals to the superior colliculus and nuclei of the posterior commissure prior to terminating in various thalamic regions (VLc and VPLo) (Carpenter, pp. 241- 243)

Answer 108

**A. 1,2, and 3 are correct ** ## Footnote Some excitatory effects of the sympathetic nervous system that lack parasympathetic opposition include splenic capsule contraction, sweating and piloerection, and elevation of the upper eyelid by the superior tarsal muscle of JVluller. Gastrointestinal peristalsis, bladder wall contraction, bronchial size, pupillary diameter, heart rate, and blood pressure can all be oppositionally altered by the sympathetic and parasympathetic nervous system (DeMyer, p. 92).

Answer 109

**A. Hyperextension and axial loading ** ## Footnote The mechanism of most modern hangman's fractures results from hyperextension and axial loading (diving and motor vehicle aCCidents), while judicial hangings often resulted in hyperextension and distractive forces from submeatal Imot placement. Patients rarely require surgical intervention for this type of fracture, which is typically reserved for irreducible fractures, failure of external immobilization, traumatic C2-3 disc herniation (with canal compromise and progressive neurologic deficit), and established nonunion. All fusion techniques typically involve fusing C2 to C3, although the majority of patients can be successfully treated with a cervical collar, SOMI brace, or halo vest (most common) (Greenberg, pp. 704-706).

Answer 110

**D. Odontoid screw ** ## Footnote The mechanism of most modern hangman's fractures results from hyperextension and axial loading (diving and motor vehicle aCCidents), while judicial hangings often resulted in hyperextension and distractive forces from submeatal Imot placement. Patients rarely require surgical intervention for this type of fracture, which is typically reserved for irreducible fractures, failure of external immobilization, traumatic C2-3 disc herniation (with canal compromise and progressive neurologic deficit), and established nonunion. All fusion techniques typically involve fusing C2 to C3, although the majority of patients can be successfully treated with a cervical collar, SOMI brace, or halo vest (most common) (Greenberg, pp. 704-706).

Answer 111

**E. Naevus flammeus** ## Footnote IGippel-Feil syndrome ranges from fusion of only a few vertebral bodies to fusion of the entire spine. It results from failure of somite segregation between 3 and 8 weeks' gestation. The classic triad (usually present in < 50% of people) includes low posterior hairline , shortened neck (brevicollis), and limited necl( motion. It may occur in conjunction with various other abnormalities includil1g basilar impression, atlantoaxial fusion, facial asymmetry, torticollis, pterygium colli (neck webbing), scoliosis, and Sprengel's deformity (25% of cases). Sprengel's deformity results in a raised scapula due to failed migration from its region of formation in the neck. Systemic congenital abnormalities may also occur, including deafness (30%), unilateral absence of a kidney, and cardiopulmonary complications. Treatment is usually directed at detecting and managing the systemic anomalies, which typically consists of a cardiac evaluation (ECG), CXR, and a renal ultrasound. Nevus t1ammeus is usually seen in patients with tethered cord syndrome (Greenberg, p. 158)

Answer 112

**C. 2.5 years ** ## Footnote The anterior fontanelle , the largest fontanelle, is diamond-shaped and normally closes by 2.5 years of age. The posterior fontanelle is triangle-shaped and closes by 2 to 3 months. The sphenoid and mastoid fontanelles are smaller, more irregular, and usually close by 2 to 3 months and! year, respectively (Greenberg, p. 138).

Answer 113

**A. 2 to 3 months ** ## Footnote The anterior fontanelle , the largest fontanelle, is diamond-shaped and normally closes by 2.5 years of age. The posterior fontanelle is triangle-shaped and closes by 2 to 3 months. The sphenoid and mastoid fontanelles are smaller, more irregular, and usually close by 2 to 3 months and! year, respectively (Greenberg, p. 138).

Answer 114

**A. 2 to 3 months ** ## Footnote The anterior fontanelle , the largest fontanelle, is diamond-shaped and normally closes by 2.5 years of age. The posterior fontanelle is triangle-shaped and closes by 2 to 3 months. The sphenoid and mastoid fontanelles are smaller, more irregular, and usually close by 2 to 3 months and! year, respectively (Greenberg, p. 138).

Answer 115

**B. 1 year ** ## Footnote The anterior fontanelle , the largest fontanelle, is diamond-shaped and normally closes by 2.5 years of age. The posterior fontanelle is triangle-shaped and closes by 2 to 3 months. The sphenoid and mastoid fontanelles are smaller, more irregular, and usually close by 2 to 3 months and! year, respectively (Greenberg, p. 138).

Answer 116

**E. All of the above ** ## Footnote Blood supply to the dura originates from the middle meningeal artery, which is a branch of the maxillary artery. It enters the skull through the foramen spinosum. The ophthalmic artery (anterior meningeal branches) and OCCipital and vertebral arteries (posterior meningeal arteries) also provide meningeal branches to the dura (Carpenter, pp. 1- 2).

Answer 117

**B. 3 ** ## Footnote The typical order of the three great vessels that originate from the aortic arch is the brachiocephalic trunk (innominate artery) followed by the left common carotid artery (LCCA) and then left subclavian artery (LSCA). This configuration is found in approximately two-thirds of all cases. A shared origin of the brachiocephalic trunk and left common carotid artery is seen in 27% (most frequent variant) of cases, while in 7% of cases the left common carotid artery arises from the proximal brachiocephalic artery instead of the aortic arch. In 1 to 2% of cases, the LCCA and LSCA share a common origin and form a left-sided brachiocephalic trunk (Osborn DCA, p. 16)

Answer 118

**C. Signs of denervation are often seen on standard Ei'"IG during the later stages of the disease** ## Footnote Formal diagnosis of myasthenia gravis depends on demonstration of response to cholinergic medications, EMG evidence of abnormal neuromuscular transmission ("jitter," "bloclting"), and identification of Circulating antibodies to Ach receptors or myofibrillar proteins such as actin, titin, myosin, and actinomycin (in approximately 85 to 90% of cases). In Single-muscle-fiber EMG studies, an electrode measures the interval between evoked potentials of muscle fibers in the same unit. This interval normally varies by "jitter", for which the temporal limits have been defined. In myasthenia gravis, "jitter" is increased. If muscle fibers are not activated due to abnormal neuromuscular transmission, it is called "bloclting." Ivlyasthenia gravis is characterized by both "bloclting" and increased "jitter," although these findings are not specific for myasthenia gravis, as other disorders may show a similar response on EMG studies. Signs of denervation are almost never seen in disorders of ACh release unless other conditions supervene. Cholinergic medications should be stopped once an endotracheal tube has been placed to reduce the amount of pulmonary secretions. Prednisone, plasmapheresis, and IVIG therapy have all been used in patients with generalized disease and/or respiratory crisis. Thymectomy is generally recommended for patients with generalized myasthenia gravis, not ocular myasthenia (Merritt, pp. 723- 726).

Answer 119

**G. Maroteaux-Lamy **

Answer 120

**F. Morquio B **

Answer 121

**C. Sanfilippo A **

Answer 122

**E. MorquioA **

Answer 123

**B. Hunter **

Answer 124

**A. I-Iurler **

Answer 125

**B. Cerebral cortex ** ## Footnote The largest quantity of afferents projecting to the striatum originate in the cerebral cortex, although the amygdala, intralaminar nuclei of the thalamus, the substantia nigra , and dorsal raphe nucleus send fibers to various parts of the striatum as well (Carpenter, pp. 332 - 336).

Answer 126

**D. Status marmoratus of the corpus striatum and thalamus ** ## Footnote Athetoid movements are slow, writhing movements predominately of the hand and wrist, while dystonia characteristically affects the axial muscles. The lesion "status marmoratus" characterizes one form of cerebral palsy, which consists of a marbled appearance of the corpus striatum and thalamus secondary to perinatal hypoxia. Hypoxic damage in these areas results in overgrowth of astrocytes as part of the healing process. Oligodendrocytes then mistakenly myelillate astrocytic processes, which causes white patches to appear in the nuclei, giving them a marbled appearance . Damage to the striatum and thalamus from other causes such as infarcts may also result in athetosis. Lesions of the substantia nigra can result in rigidity and resting tremor, which are some of the hallmarks of Parkinson's disease. Lesions of the subthalami

Answer 127

**B. Substantia nigra ** ## Footnote Athetoid movements are slow, writhing movements predominately of the hand and wrist, while dystonia characteristically affects the axial muscles. The lesion "status marmoratus" characterizes one form of cerebral palsy, which consists of a marbled appearance of the corpus striatum and thalamus secondary to perinatal hypoxia. Hypoxic damage in these areas results in overgrowth of astrocytes as part of the healing process. Oligodendrocytes then mistakenly myelillate astrocytic processes, which causes white patches to appear in the nuclei, giving them a marbled appearance . Damage to the striatum and thalamus from other causes such as infarcts may also result in athetosis. Lesions of the substantia nigra can result in rigidity and resting tremor, which are some of the hallmarks of Parkinson's disease. Lesions of the subthalami

Answer 128

**C. Vicinity of red nucleus** ## Footnote Athetoid movements are slow, writhing movements predominately of the hand and wrist, while dystonia characteristically affects the axial muscles. The lesion "status marmoratus" characterizes one form of cerebral palsy, which consists of a marbled appearance of the corpus striatum and thalamus secondary to perinatal hypoxia. Hypoxic damage in these areas results in overgrowth of astrocytes as part of the healing process. Oligodendrocytes then mistakenly myelillate astrocytic processes, which causes white patches to appear in the nuclei, giving them a marbled appearance . Damage to the striatum and thalamus from other causes such as infarcts may also result in athetosis. Lesions of the substantia nigra can result in rigidity and resting tremor, which are some of the hallmarks of Parkinson's disease. Lesions of the subthalami

Answer 129

**A. .Amygdala ** ## Footnote Athetoid movements are slow, writhing movements predominately of the hand and wrist, while dystonia characteristically affects the axial muscles. The lesion "status marmoratus" characterizes one form of cerebral palsy, which consists of a marbled appearance of the corpus striatum and thalamus secondary to perinatal hypoxia. Hypoxic damage in these areas results in overgrowth of astrocytes as part of the healing process. Oligodendrocytes then mistakenly myelillate astrocytic processes, which causes white patches to appear in the nuclei, giving them a marbled appearance . Damage to the striatum and thalamus from other causes such as infarcts may also result in athetosis. Lesions of the substantia nigra can result in rigidity and resting tremor, which are some of the hallmarks of Parkinson's disease. Lesions of the subthalami

Answer 130

**E. Subthalamic nucleus ** ## Footnote Athetoid movements are slow, writhing movements predominately of the hand and wrist, while dystonia characteristically affects the axial muscles. The lesion "status marmoratus" characterizes one form of cerebral palsy, which consists of a marbled appearance of the corpus striatum and thalamus secondary to perinatal hypoxia. Hypoxic damage in these areas results in overgrowth of astrocytes as part of the healing process. Oligodendrocytes then mistakenly myelillate astrocytic processes, which causes white patches to appear in the nuclei, giving them a marbled appearance . Damage to the striatum and thalamus from other causes such as infarcts may also result in athetosis. Lesions of the substantia nigra can result in rigidity and resting tremor, which are some of the hallmarks of Parkinson's disease. Lesions of the subthalami

Answer 131

**E. All of the above** ## Footnote The thalamus receives its arterial supply from the anterior choroidal artery (lCA) and thalamoperforating arteries (PComA and basilar artery) as well as the thalamogeniculate and posterior choroidal arteries (PCA). Infarctions may occur in each of these thalamic territories and cause various clinical syndromes, depending on which thalamic nuclei are involved (Carpenter, pp. 441- 450).

Answer 132

**B. Alzheimer's disease ** ## Footnote Note the prominent diffuse plaques traversed by neuronal processes in this patient with Alzheimer's disease . Diffuse amyloid plaques are extracellular, ill-defined focal aggregates of amyloid and preamyloid material and are approximately 60 to 300 mm in diameter. Neuronal cell processes traversing the plaque typically appear normal and do not contain tau protein (Ellison, pp. 553- 557).

Answer 133

**E. I-Iyperflexion and compression ** ## Footnote Occipital condylar and burst fractures are often the result of purely axial compressive forces on a neutral neck, while teardrop and compression-wedge fractures result from compressive force on a flexed neck Other injury or fracture patterns in the cervical spine include unilateral (axial rotation, flexing) and bilateral locked (hyperflexion and distraction) facets, Chance fracture (flexion, distraction), and unilateral facet fracture (lateral bending, compression). Odontoid fractures usually result from hyperflexion injuries and result in anterior displacement of C2 on C3. (Greenberg, pp. 702- 714; Youmans, pp. 517- 523, 4896- 4897, 4927; Harris, pp. 69- 91).

Answer 134

**D. Hyperflexion and axial rotation ** ## Footnote Occipital condylar and burst fractures are often the result of purely axial compressive forces on a neutral neck, while teardrop and compression-wedge fractures result from compressive force on a flexed neck Other injury or fracture patterns in the cervical spine include unilateral (axial rotation, flexing) and bilateral locked (hyperflexion and distraction) facets, Chance fracture (flexion, distraction), and unilateral facet fracture (lateral bending, compression). Odontoid fractures usually result from hyperflexion injuries and result in anterior displacement of C2 on C3. (Greenberg, pp. 702- 714; Youmans, pp. 517- 523, 4896- 4897, 4927; Harris, pp. 69- 91).

Answer 135

**A. A."jalloading/compression on neutral neck ** ## Footnote Occipital condylar and burst fractures are often the result of purely axial compressive forces on a neutral neck, while teardrop and compression-wedge fractures result from compressive force on a flexed neck Other injury or fracture patterns in the cervical spine include unilateral (axial rotation, flexing) and bilateral locked (hyperflexion and distraction) facets, Chance fracture (flexion, distraction), and unilateral facet fracture (lateral bending, compression). Odontoid fractures usually result from hyperflexion injuries and result in anterior displacement of C2 on C3. (Greenberg, pp. 702- 714; Youmans, pp. 517- 523, 4896- 4897, 4927; Harris, pp. 69- 91).

Answer 136

**F. Hypertlexion and distraction ** ## Footnote Occipital condylar and burst fractures are often the result of purely axial compressive forces on a neutral neck, while teardrop and compression-wedge fractures result from compressive force on a flexed neck Other injury or fracture patterns in the cervical spine include unilateral (axial rotation, flexing) and bilateral locked (hyperflexion and distraction) facets, Chance fracture (flexion, distraction), and unilateral facet fracture (lateral bending, compression). Odontoid fractures usually result from hyperflexion injuries and result in anterior displacement of C2 on C3. (Greenberg, pp. 702- 714; Youmans, pp. 517- 523, 4896- 4897, 4927; Harris, pp. 69- 91).

Answer 137

**H. Lateral bending and compression ** ## Footnote Occipital condylar and burst fractures are often the result of purely axial compressive forces on a neutral neck, while teardrop and compression-wedge fractures result from compressive force on a flexed neck Other injury or fracture patterns in the cervical spine include unilateral (axial rotation, flexing) and bilateral locked (hyperflexion and distraction) facets, Chance fracture (flexion, distraction), and unilateral facet fracture (lateral bending, compression). Odontoid fractures usually result from hyperflexion injuries and result in anterior displacement of C2 on C3. (Greenberg, pp. 702- 714; Youmans, pp. 517- 523, 4896- 4897, 4927; Harris, pp. 69- 91).

Answer 138

**E. I-Iyperflexion and compression ** ## Footnote Occipital condylar and burst fractures are often the result of purely axial compressive forces on a neutral neck, while teardrop and compression-wedge fractures result from compressive force on a flexed neck Other injury or fracture patterns in the cervical spine include unilateral (axial rotation, flexing) and bilateral locked (hyperflexion and distraction) facets, Chance fracture (flexion, distraction), and unilateral facet fracture (lateral bending, compression). Odontoid fractures usually result from hyperflexion injuries and result in anterior displacement of C2 on C3. (Greenberg, pp. 702- 714; Youmans, pp. 517- 523, 4896- 4897, 4927; Harris, pp. 69- 91).

Answer 139

**A. A."jalloading/compression on neutral neck ** ## Footnote Occipital condylar and burst fractures are often the result of purely axial compressive forces on a neutral neck, while teardrop and compression-wedge fractures result from compressive force on a flexed neck Other injury or fracture patterns in the cervical spine include unilateral (axial rotation, flexing) and bilateral locked (hyperflexion and distraction) facets, Chance fracture (flexion, distraction), and unilateral facet fracture (lateral bending, compression). Odontoid fractures usually result from hyperflexion injuries and result in anterior displacement of C2 on C3. (Greenberg, pp. 702- 714; Youmans, pp. 517- 523, 4896- 4897, 4927; Harris, pp. 69- 91).

Answer 140

**G. I-Iypertlexion ** ## Footnote Occipital condylar and burst fractures are often the result of purely axial compressive forces on a neutral neck, while teardrop and compression-wedge fractures result from compressive force on a flexed neck Other injury or fracture patterns in the cervical spine include unilateral (axial rotation, flexing) and bilateral locked (hyperflexion and distraction) facets, Chance fracture (flexion, distraction), and unilateral facet fracture (lateral bending, compression). Odontoid fractures usually result from hyperflexion injuries and result in anterior displacement of C2 on C3. (Greenberg, pp. 702- 714; Youmans, pp. 517- 523, 4896- 4897, 4927; Harris, pp. 69- 91).

Answer 141

**C. Adaman tinomatous craniopharyngioma ** ## Footnote Note the squamous cells, peripheral palisading of nuclei, and nodules of wet keratin in this adamantinomatous craniopharyngioma (Ellison, pp. 724-727; WHO, pp. 244- 246).

Answer 142

**E. Cralliovertebraljunction abnormality** ## Footnote Approximately 90% of cases of vertigo are likely secondary to lesions of the vestibular end organs or vestibular nerves, while the rest usually originate from the central nervous system, including craniocervical junction abnormalities (Merritt, pp. 28-30).

Answer 143

**D. Only 4 is correct ** ## Footnote The supratentorial dura is innervated primarily by branches of the trigeminal nerve, while the infra tentorial dura is innervated by branches of the vagus and lower cervical spinal nerves (Carpenter, p. 2).

Answer 144

**D. Disc herniation ** ## Footnote Depicted here is an axial and parasagittal MIU showing a soft (mainly disc material) posterolateral disc herniation of the cervical spine that is eccentric to the left. Considering that this disc herniation is not purely central , it may be runenable to a posterolateral procedure in an attempt to preserve vocal cord function (posterior keyhole laminotomy) in this wedding singer. Over 90% of patients with acute cervical radiculopathy will improve with nonsurgical therapy including adequate pain medication and antiinllammatories. Surgery is indicated for those who fail to improve or develop progressive neurologic deficits while undergoing nonsurgical therapy. A number of large series have reported good or excellent results in 90 to 96% of patients who underwent a posterior approach for such disc herniations (Greenberg, pp. 310-314).

Answer 145

**C. Posterior keyhole laminotomy** ## Footnote Depicted here is an axial and parasagittal MIU showing a soft (mainly disc material) posterolateral disc herniation of the cervical spine that is eccentric to the left. Considering that this disc herniation is not purely central, it may be runenable to a posterolateral procedure in an attempt to preserve vocal cord function (posterior keyhole laminotomy) in this wedding singer. Over 90% of patients with acute cervical radiculopathy will improve with nonsurgical therapy including adequate pain medication and antiinllammatories. Surgery is indicated for those who fail to improve or develop progressive neurologic deficits while undergoing nonsurgical therapy. A number of large series have reported good or excellent results in 90 to 96% of patients who underwent a posterior approach for such disc herniations (Greenberg, pp. 310-314).

Answer 146

**B. 1 and 3 are correct ** ## Footnote Yolk sac tumor is a germ cell tumor that exhibits loosely arranged cells with clear cytoplasm and prominent eosinophilic bodies. Yolk sac tumors are positive for AFP, and they often exhibit Schiller-Duval bodies (Ellison, p. 683).

Answer 147

**B. 1 and 3 are correct ** ## Footnote IHeticulous preoperative anesthetic workup is extremely important for acromegalic patients, since they frequently exhibit cardiomyopathy and macroglossia, which can be associated with a difficult airway (Youmans, p. 569).

Answer 148

**C. GABA/enkephalin ** ## Footnote HD primarily affects the GABA/enkephalin projections from the striatum to the external segment of the globus pallidus (indirect pathway), resulting in thalamic facilitation of motor cortical areas and hyperkinesia (Merritt, pp. 659- 662).

Answer 149

**E. Adenohypophysis** ## Footnote Note the prominent lobules of cells with an intervening vascular network of sinusoids in this photomicrograph of a normal adenohypophysis (Ellison, p. 716).

Answer 150

**C. J'vIaternal hyperthermia on gestational days 20 to 26 ** ## Footnote Meckel-Gruber syndrome typically includes encephalocele, microcephaly, microphthalmia , cleft lip, polydactyly, polycystic kidneys, congenital heart disease , and ambiguous genitalia; it is most often associated with maternal hyperthermia on gestational days 20 to 26 (Rudolph, p. 156).

Answer 151

**D. J\'liniature endplate potential ** ## Footnote The release of a single quantum of acetylcholine (10,000 molecules of ACh) produces a miniature endplate potential (J'I'IEPP) in the postsynaptic membrane, which is not significant enough to generate an action potential. The summation of several quanta is required to induce enough depolarization in the postsynaptic cell membrane to result in an action potential (Kandel, pp. 255-262).

Answer 152

**B. cGMP ** ## Footnote Nitric oxide (NO) is produced in neurons by the Ca2 +/calmodulin-dependent enzyme NO synthase. NO, in turn, stimulates the synthesis of cGMP through the action of guanylyl cyclase, an enzyme that converts GTP to cGMP. NO acts locally and is primarily released from endothelial cells to induce smooth muscle relaxation and blood vessel dilation (Kandel, p. 239).

Answer 153

**C. Sulfation of arginine residues ** ## Footnote Neuronal cytoplasmic organelles include rough and smooth endoplasmic reticulum, endosomes, secretory vesicles, lysosomes, peroxisomes, mitochondria, and the Golgi apparatus. Proteins and phospholipids destined for secretion are initially synthesized in the rough endoplasmic reticulum (rER). These products are then transported to the Golgi apparatus via transport vesicles for processing (although N-linked glycosylation and glycolipid conjugation are initiated in the rER). The Golgi complex further modifies these proteins by adding polysaccharides, which can direct specific proteins to secretory vesicles, lysosomes, and the plasma membrane. Golgi processing includes glycosylation reactions (O-linked and N-linked glycosylation), proteoglycan formation, polysaccharide phosphorylation, attachment of fatty acids, and sulfation of tyrosine (not arginine) and sugar residues. This processing increases the hydrophilicity (solubility) of these proteins, increases their biological activity, or helps delay their degradation by proteases. Clathrin coats facilitate the budding of vesicles from the Golgi complex. Secretory vesicles (dense-core vesicles) are targeted primarily to axon terminals, where they participate in calciumregulated exocytosis after action potential propagation (Kandel, pp. 67-71, 94- 97)

Answer 154

**B. Tight junctions between nonfenestrated endothelial cells ** ## Footnote The BBB is primarily composed of tight junctions between nonfenestrated endothelial cells. These endothelial cells are also deficient in vesicular transport compared to endothelial cells elsewhere in the body, which further contributes to the selectivity of the BBB. The resistance provided by the tight junctions between endothelial cells in the brain is extremely high . Substances may cross the BBB by diffUSion, active transport, carrier-mediated transport, and through ion channels. Lipid-soluble substances readily diffuse across endothelial cell membranes into the brain; hence the permeability of many substances is directly related to their lipid-solubility. Specific carrier-mediated transport is responsible for the entry of most substances into the brain. The glucose transporter (Glutl) is energy-independent, thus transporting only glucose down its concentration gradient from the bloodstream into the brain. There are also three distinct carrier systems for amino acid transport across the BBB. The L system transports large neutral branched-chain amino acids and L-DOPA into the brain. A transport system that is a member of the multiple-drug-resistance (MDR) transporter family found in tumor cells removes a wide range of hydrophobic toxins and chemotherapeutic agents from the brain. Additionally, specific ion channels allow the movement of electrolytes across the BBB. A metabolic BBB also exists due to the presence of certain enzymes that rapidly metabolize substances as they enter the CNS. An example is the high concentration of DOPA decarboxylase in epithelial cells that rapidly metabolize L-DOPA as it enters the brain

Answer 155

**D. Substantia nigra ** ## Footnote The substantia nigra has the highest concentration of substance P in the brain. Striatonigral projections from the caudate nucleus and putamen contain GABA, substance P, and en kephalin (Carpenter, pp. 215- 221).

Answer 156

**C. Olfactory groove meningioma ** ## Footnote Note that the anterior cerebral arteries are being pushed upward on this lateral angiogram, depicting an olfactory groove meningioma. These lesions often grow insidiously, causing gradual compression of the frontal lobes; thus they are quite large and bilateral by the time of presentation. Common signs/symptoms may include headaches, personality changes, visual loss, anosmia, and seizures. A bifrontal transbasal approach is frequently used in resecting these tumors, although a unilateral subfrontal or frontotemporal (pterional) craniotomy can also be used. The anterior and posterior ethmoid arteries typically supply olfactory groove meningiomas (Kaye and Blacl(, pp. 523-532; Youmans, pp. 1115-1115).

Answer 157

**E. The anterior and posterior ethmoidal arteries ** ## Footnote Note that the anterior cerebral arteries are being pushed upward on this lateral angiogram, depicting an olfactory groove meningioma. These lesions often grow insidiously, causing gradual compression of the frontal lobes; thus they are quite large and bilateral by the time of presentation. Common signs/symptoms may include headaches, personality changes, visual loss, anosmia, and seizures. A bifrontal transbasal approach is frequently used in resecting these tumors, although a unilateral subfrontal or frontotemporal (pterional) craniotomy can also be used. The anterior and posterior ethmoid arteries typically supply olfactory groove meningiomas (Kaye and Blacl(, pp. 523-532; Youmans, pp. 1115-1115).

Answer 158

**A. X-linked recessive** ## Footnote Charcot-Ma rie-Tooth (CMT) disease, or peroneal muscular atrophy, accounts for about 90% of all hereditary neuropathies, of which there are three types. ClI'IT-l, the most common , is autosomal dominant and is a demyelinating disease that results in a dista l sensorimotor neuropathy. It results from mutations in peripheral myelin protein 22 (PMP-22), exhibits slowed nerve conduction velocities, and exhibits onion-bulb formations on histopathologic studies. CMT-2 resembles C)\'IT-l but results in axonal degeneration instead of demyelination. CMT-3 , also Imown as Dejerine-Sottas syndrome, is autosomal dominant and results in a hypertrophic demyelinating neuropathy. DMD is an X-linked recessive condition that results from mutation of the dystrophin gene, located at Xp21. Patients often have difficulty rising from the ground and rely heavily on the anTIS to raise the torso and legs (Gowers' sign). These patients may also exhibit toe-walking and develop an exaggerated lumbar lordosis or scoliosis as well as pseudohypertrophy of the calves from fibrosis and fatty infiltration of degenerating muscle. MD is a trinucleotide repeat disorder that results from mutation of the dystrophia myotonica protein kinase gene on chromosome 19. It is a pleiotropiC, autosomal dominant disorder affecting the skeletal muscle, heart, eyes, and exocrine glands. The myopathy of MD affects several cranial nerves (ptosis, dysarthria, dysphagia) and the distal extremities (finger flexors and extensors). Patients exhibit myotonia (impaired muscle relaxation), cataracts, frontal balding, testicular atrophy, retinal degeneration, cardiomyopathy, and an increased incidence of mental retardation. FSHMD is an autosomal dominant disorder that results in scapular winging, facial wealmess, shoulder girdle wealmess, and lower extremity wealmess (Merritt, pp. 737- 746)

Answer 159

**B. Autosomal dominant ** ## Footnote Charcot-Ma rie-Tooth (CMT) disease, or peroneal muscular atrophy, accounts for about 90% of all hereditary neuropathies, of which there are three types. ClI'IT-l, the most common , is autosomal dominant and is a demyelinating disease that results in a dista l sensorimotor neuropathy. It results from mutations in peripheral myelin protein 22 (PMP-22), exhibits slowed nerve conduction velocities, and exhibits onion-bulb formations on histopathologic studies. CMT-2 resembles C)\'IT-l but results in axonal degeneration instead of demyelination. CMT-3 , also Imown as Dejerine-Sottas syndrome, is autosomal dominant and results in a hypertrophic demyelinating neuropathy. DMD is an X-linked recessive condition that results from mutation of the dystrophin gene, located at Xp21. Patients often have difficulty rising from the ground and rely heavily on the anTIS to raise the torso and legs (Gowers' sign). These patients may also exhibit toe-walking and develop an exaggerated lumbar lordosis or scoliosis as well as pseudohypertrophy of the calves from fibrosis and fatty infiltration of degenerating muscle. MD is a trinucleotide repeat disorder that results from mutation of the dystrophia myotonica protein kinase gene on chromosome 19. It is a pleiotropiC, autosomal dominant disorder affecting the skeletal muscle, heart, eyes, and exocrine glands. The myopathy of MD affects several cranial nerves (ptosis, dysarthria, dysphagia) and the distal extremities (finger flexors and extensors). Patients exhibit myotonia (impaired muscle relaxation), cataracts, frontal balding, testicular atrophy, retinal degeneration, cardiomyopathy, and an increased incidence of mental retardation. FSHMD is an autosomal dominant disorder that results in scapular winging, facial wealmess, shoulder girdle wealmess, and lower extremity wealmess (Merritt, pp. 737- 746)

Answer 160

**B. Autosomal dominant ** ## Footnote Charcot-Ma rie-Tooth (CMT) disease, or peroneal muscular atrophy, accounts for about 90% of all hereditary neuropathies, of which there are three types. ClI'IT-l, the most common , is autosomal dominant and is a demyelinating disease that results in a dista l sensorimotor neuropathy. It results from mutations in peripheral myelin protein 22 (PMP-22), exhibits slowed nerve conduction velocities, and exhibits onion-bulb formations on histopathologic studies. CMT-2 resembles C)\'IT-l but results in axonal degeneration instead of demyelination. CMT-3 , also Imown as Dejerine-Sottas syndrome, is autosomal dominant and results in a hypertrophic demyelinating neuropathy. DMD is an X-linked recessive condition that results from mutation of the dystrophin gene, located at Xp21. Patients often have difficulty rising from the ground and rely heavily on the anTIS to raise the torso and legs (Gowers' sign). These patients may also exhibit toe-walking and develop an exaggerated lumbar lordosis or scoliosis as well as pseudohypertrophy of the calves from fibrosis and fatty infiltration of degenerating muscle. MD is a trinucleotide repeat disorder that results from mutation of the dystrophia myotonica protein kinase gene on chromosome 19. It is a pleiotropiC, autosomal dominant disorder affecting the skeletal muscle, heart, eyes, and exocrine glands. The myopathy of MD affects several cranial nerves (ptosis, dysarthria, dysphagia) and the distal extremities (finger flexors and extensors). Patients exhibit myotonia (impaired muscle relaxation), cataracts, frontal balding, testicular atrophy, retinal degeneration, cardiomyopathy, and an increased incidence of mental retardation. FSHMD is an autosomal dominant disorder that results in scapular winging, facial wealmess, shoulder girdle wealmess, and lower extremity wealmess (Merritt, pp. 737- 746)

Answer 161

**B. Autosomal dominant ** ## Footnote Charcot-Ma rie-Tooth (CMT) disease, or peroneal muscular atrophy, accounts for about 90% of all hereditary neuropathies, of which there are three types. ClI'IT-l, the most common , is autosomal dominant and is a demyelinating disease that results in a dista l sensorimotor neuropathy. It results from mutations in peripheral myelin protein 22 (PMP-22), exhibits slowed nerve conduction velocities, and exhibits onion-bulb formations on histopathologic studies. CMT-2 resembles C)\'IT-l but results in axonal degeneration instead of demyelination. CMT-3 , also Imown as Dejerine-Sottas syndrome, is autosomal dominant and results in a hypertrophic demyelinating neuropathy. DMD is an X-linked recessive condition that results from mutation of the dystrophin gene, located at Xp21. Patients often have difficulty rising from the ground and rely heavily on the anTIS to raise the torso and legs (Gowers' sign). These patients may also exhibit toe-walking and develop an exaggerated lumbar lordosis or scoliosis as well as pseudohypertrophy of the calves from fibrosis and fatty infiltration of degenerating muscle. MD is a trinucleotide repeat disorder that results from mutation of the dystrophia myotonica protein kinase gene on chromosome 19. It is a pleiotropiC, autosomal dominant disorder affecting the skeletal muscle, heart, eyes, and exocrine glands. The myopathy of MD affects several cranial nerves (ptosis, dysarthria, dysphagia) and the distal extremities (finger flexors and extensors). Patients exhibit myotonia (impaired muscle relaxation), cataracts, frontal balding, testicular atrophy, retinal degeneration, cardiomyopathy, and an increased incidence of mental retardation. FSHMD is an autosomal dominant disorder that results in scapular winging, facial wealmess, shoulder girdle wealmess, and lower extremity wealmess (Merritt, pp. 737- 746)

Answer 162

**B. Autosomal dominant ** ## Footnote Charcot-Ma rie-Tooth (CMT) disease, or peroneal muscular atrophy, accounts for about 90% of all hereditary neuropathies, of which there are three types. ClI'IT-l, the most common , is autosomal dominant and is a demyelinating disease that results in a dista l sensorimotor neuropathy. It results from mutations in peripheral myelin protein 22 (PMP-22), exhibits slowed nerve conduction velocities, and exhibits onion-bulb formations on histopathologic studies. CMT-2 resembles C)\'IT-l but results in axonal degeneration instead of demyelination. CMT-3 , also Imown as Dejerine-Sottas syndrome, is autosomal dominant and results in a hypertrophic demyelinating neuropathy. DMD is an X-linked recessive condition that results from mutation of the dystrophin gene, located at Xp21. Patients often have difficulty rising from the ground and rely heavily on the anTIS to raise the torso and legs (Gowers' sign). These patients may also exhibit toe-walking and develop an exaggerated lumbar lordosis or scoliosis as well as pseudohypertrophy of the calves from fibrosis and fatty infiltration of degenerating muscle. MD is a trinucleotide repeat disorder that results from mutation of the dystrophia myotonica protein kinase gene on chromosome 19. It is a pleiotropiC, autosomal dominant disorder affecting the skeletal muscle, heart, eyes, and exocrine glands. The myopathy of MD affects several cranial nerves (ptosis, dysarthria, dysphagia) and the distal extremities (finger flexors and extensors). Patients exhibit myotonia (impaired muscle relaxation), cataracts, frontal balding, testicular atrophy, retinal degeneration, cardiomyopathy, and an increased incidence of mental retardation. FSHMD is an autosomal dominant disorder that results in scapular winging, facial wealmess, shoulder girdle wealmess, and lower extremity wealmess (Merritt, pp. 737- 746)

Answer 163

**E. All of the above** ## Footnote The common peroneal nerve (L4-S2) innervates the extensors and adductors of the leg (and part of the biceps femoris) and gives rise to the latera l sural cutaneous nerve (to the inferolateral leg), the deep peroneal ne rve, and the superficial peroneal nerve. The deep peroneal nerve innervates the tibiaUs anterior, extensor hallucis longus, and extensor cligitorum longus muscles. The superficial peroneal nerve innervates the peroneus longus/brevis (foot eversion) and the skin of the distal anterior leg, dorsum of the foot , and digits. Lesions of the common peroneal nerve mainly result in paralysis of dorsiflexion (footdrop) and foot eversion (Patten, p. 311; Greenberg, pp. 522, 545).

Answer 164

**B. CA2 ** ## Footnote Hippocampal sclerosis usually has a very characteristic pattern in patients with mesial temporal lobe epilepsy. The greatest amount of damage is usually seen in the CAl and CA4 sectors, while the least amount of damage occurs in CA2. Synaptic reorganization of granule cell mossy fibe rs is usually a characteristic feature of hippocampal sclerosis (Committee on Education in Neurological Surgery, pp. 20, 110; Mathem et al., pp. 105- 113).

Answer 165

**C. Nephrocalcinosis can accompany this disorder ** ## Footnote Nephrocalcinosis frequently accompanies type I, or distal, renal tubular acidosis (RTA). In type 1 RTA, the proximal reabsorption of ICO~ is adequate, but the ability of the distal tubule to secrete H+ ions is inadequate. The urine pH remains above 5.5, and hypolwlemia, hypercalcemia , nephrocalcinosis, and osteomalacia frequently accompany this abnormality. lvloderate amounts of bicarbonate therapy may correct the acidosis. With type II RTA, the ability of the proximal tubule to reabsorb HCO:; is compromised; HCO~ is lost in the urine and acidemia develops secondary to the inability of the distal tubule to reabsorb the flood of HCO~. Eventually, the serum I-ICO:; decreases to a point whe re the proximal renal tubule can reabsorb most of the reduced HCO~ load, while the remainder is reclaimed in the distal tubule, This maintains the urine pH < 5.5. W is frequently low with proximal type II RT A. Type IV RTA is seen with hyporeninemic hypoaldosteronism, which is characterized by a mild acidosis associated with increased Ie levels compared to the low levels seen with types I and II RTA. The elevated K+ suppresses ammonia production, which sustains the acidosis (Fishman, pp. 138-139).

Answer 166

**A. Oysembryoplastic neuroepithelial tumor (ONT)** ## Footnote This lesion is most consistent with a DNT (WIIO grade I). Patients usually present with long-standing drug-resistant partial seizures that begin before the age of 20. They are usually found in the temporal lobe or other supratentorial location and typically encompass the cerebral cortex. On occasion, they appear to deform the overlying calvarium, a finding that furthe r supports the diagnosis of DNT. The histologic hallmark of this tumor is the glioneuronal element, which is shown here to consist of a free-floating neuron in a microcyst surrounded by oligodendroglia I-like cells (Ellison, pp. 659- 661; WHO, pp. 103-106).

Answer 167

**C. Glioneuronal element ** ## Footnote This lesion is most consistent with a DNT (WIIO grade I). Patients usually present with long-standing drug-resistant partial seizures that begin before the age of 20. They are usually found in the temporal lobe or other supratentorial location and typically encompass the cerebral cortex. On occasion, they appear to deform the overlying calvarium, a finding that furthe r supports the diagnosis of DNT. The histologic hallmark of this tumor is the glioneuronal element, which is shown here to consist of a free-floating neuron in a microcyst surrounded by oligodendroglia I-like cells (Ellison, pp. 659- 661; WHO, pp. 103-106).

Answer 168

**B. Seizures ** ## Footnote This lesion is most consistent with a DNT (WIIO grade I). Patients usually present with long-standing drug-resistant partial seizures that begin before the age of 20. They are usually found in the temporal lobe or other supratentorial location and typically encompass the cerebral cortex. On occasion, they appear to deform the overlying calvarium, a finding that furthe r supports the diagnosis of DNT. The histologic hallmark of this tumor is the glioneuronal element, which is shown here to consist of a free-floating neuron in a microcyst surrounded by oligodendroglia I-like cells (Ellison, pp. 659- 661; WHO, pp. 103-106).

Answer 169

**D. Early decrease in mean corpuscular hemoglobin concentration (MCHC) ** ## Footnote Although the MCV progressively decreases as the anemia becomes more severe , the MCHC usually remains normal until the hematocrit values drop below 30%. As the anemia becomes more marked, the red blood cells become progressively more distorted (poi!,ilocytosis), the TIBC begins to increase, the ferritin levels drop, the serum iron stores begin to fall , and the bone marrow iron stores become depleted. Causes of anemia with low MCV include iron deficiency (pregnancy, GI bleeding), thalassemia , anemia of chronic inflammation, sideroblastic anemia, and aluminum toxicity (Fishman, pp. 345- 347; Barl~er, pp. 620-623).

Answer 170

**B. 1 and3 are correct ** ## Footnote The addition of phenytoin and phenobarbital most often increases the serum concentration of valproate (Geyer, p.213).

Answer 171

**C. Polymyositis rarely responds to steroids, whereas IBi'vI may respond in some cases ** ## Footnote IBM affects proximal limb muscles, but in contrast to polymyositis, is much more likely to affect the distal muscles of the legs. It commonly occurs in men after the age of SO and has less of an association with autoimmune and collagen vascular diseases than polymyositis. Whereas polymyositis does respond to steroids, IBM has no widely accepted the rapy, as steroids have shown minimal benefit (Merritt, pp. 767- 768).

Answer 172

**E. Oraves' disease** ## Footnote Graves' disease (hyperthyroidism) does not typically cause carpal tunnel syndrome but is more likely to produce ophthalmopathy, including a "stare " and "lid lag," and thyroid exophthalmos from mucinous and cellular infiltration of the extraocular llluscles (inferior and medial recti most commonly affected). Common e tiologies of carpal tunnel syndrome include rheumatoid arthritis, pregnancy, acromegaly, amyloidosis, myxedema, and birth control pills (Greenberg, pp. 536- 539).

Answer 173

**C. Vertebral artery dissection ** ## Footnote This constellation of signs/symptoms is most consistent with the lateral medullary syndrome (of Wallenberg). In a young patient who was subjected to strenuous exercise and extreme neck movements, the most lll,ely diagnosis is vertebral artery dissection (Greenberg, pp. 849-850).

Answer 174

**C. Tumor growth factor (1'01"-0:) ** ## Footnote EGF and TGF-a. bind to EGFR with equal affinity; however, whereas EGFR is commonly upregulated in highgrade malignancies, EGF is rarely over-expressed. In contrast, TGF-a. is frequently expressed in gliomas, which binds to EGFR and stimulates tyrosine kinase-specific activity, leading to further cell transformation. Thus, it is believed that TGF-a. is the primary ligand binding to EGFR in malignant gliomas (Youmans, pp. 726-727).

Answer 175

**E. Magnesium** ## Footnote TNF-a., IL-lb, IL-6, and potassium levels have been shown to increase after DAI, while magnesium-which is involved in glycolysis, oxidative phosphorylation, cellular respiration, and the synthesis of DNA, RNA, and proteinshas been shown to decrease after severe head injury (Marion, pp.40-45).

Answer 176

**B. 14 to 21 days ** ## Footnote Denervation of muscle results in fibrillation potentials and positive sharp waves within approximately 2 to 3 weel(s and 8 days, respectively. These findings persist until the muscle fibers are reinnervated (usually 3 to 4 months after mild insults) or until the denervated muscl e undergoes complete atrophy (Youmans, p. 3856).

Answer 177

**A. Arachnoiditis ** ## Footnote Note the multiple prominent irregularities and loculations located circumferentially around the margins of the dura on this CT myelogram, which is most consistent with arachnoiditis (Ramsey, pp. 739-741).

Answer 178

**E. All of the above** ## Footnote Sarcoidosis is a systemic granulomatous disease that involves the nervous system in 5% of patients (neurosarcoidosis). CNS granulomas in neurosarcoidosis can involve the cranial nerves, meninges, hypothalamus, brain parenchyma, and spinal cord. The skull base is frequently affected, and granulomas in this location may result in obstructive hydrocephalus. Cranial nerve palsies may also occur; the facial nerve is most commonly involved. Hypothalamic granulomas can result in diabetes insipidus, galactorrhea, amenorrhea, and changes in behavior, sleep patterns, and appetite. Sarcoidosis can also cause peripheral neuropathies, such as mononeuropathy multiplex. MRI often reveals the presence of CNS granulomas, and CSF exhibits a lymphocytic pleocytosis with elevations in IgG and the IgG index. Oligoclonal bands and elevated angiotensin-converting enzyme (ACE) levels can also be found in the CSF. Neurosarcoidosis can present as a self-limited monophasic illness or a chronic disease with relapses and remissions. Treatment of neurosarcoidosis involves corticosteroids (prednisone), with immunosuppressant drugs added in refractory cases (azathioprine, methotrexa te, cyclosporine) (Merritt pp. 180- 181)

Answer 179

A. Alcohol intoxication B. Left frontal lobe mass **C. A lethal closed head injury** D. Hepatic encephalopathy E. Delta rhythm ## Footnote Electrocerebral inactivity is consistent with brain death in the setting of a detailed brain death exam. It is defined as no cerebral electrical potentials greater than 2 ~IV. It is not required to pronounce brain death and is used as an ancillary test when the diagnosis is not clear. Drug intoxication (e.g., phenobarbital) and hypothermia may result in reversible electrocerebral inactivity (Greenberg, p. 130).

Answer 180

A. Torsades de polites **B. Hyperkalemia** C. Digoxin toxicity D. First-degree heart block E. Multifocal atrial tachycardia ## Footnote The most potentially serious complication of hyperkalemia is slowing of electrical heart conduction. The ECG begins to change when the serum K+ reaches approximately 6.0 mEq/L and is always abnormal when it is > 8.0 mEq/L. The earliest ECG abnormality is a tall, tapering l' wave that is most evident in the precordial leads V2 and V". As W levels increase further, the P-wave amplitude decreases and the PR interval lengthens. The P waves may eventually disappear and the QRS complex widen . The final event is ventricular asystole (Marino, pp. 654- 655).

Answer 181

E ## Footnote Occlusion of the anterior choroidal artery causes a homonymous defect in the upper and lower quadrants, with sparing of the horizontal sector (quadruple sectoranopia, B), which is usually characteristic of a lateral geniculate body infarct that is supplied by the anterior choroidal artery. The central portion of the lateral geniculate body receives blood flow primarily from the lateral posterior choroidal artery. Interruption of this vessel causes a horizontal homonymous sector defect (wedgeshaped, D). Superior homonymous quadran tic defects ("piein the sky, " E) may result from a lesion along i\-Ieyer's loop (after temporal lobectomy) or along the inferior bank of the calcarine fissure . The anterior chiasm or junctional syndrome results in a unilateral optic nerve defect of one eye and a superior temporal defect in the other eye (A) due to the loop made by the inferonasal retina of the other eye (\Villebrand's knee). Lesions located in the most anterior portion of the calcarine cortex cause a crescent-shaped defect restricted to the temporal field of the contralateral eye (monocular temporal crescent, C). This is the only retrochiasmatic lesion that may result in a strictly unilateral visual field defect (Bralis, pp. 132-140).

Answer 182

D ## Footnote Occlusion of the anterior choroidal artery causes a homonymous defect in the upper and lower quadrants, with sparing of the horizontal sector (quadruple sectoranopia, B), which is usually characteristic of a lateral geniculate body infarct that is supplied by the anterior choroidal artery. The central portion of the lateral geniculate body receives blood flow primarily from the lateral posterior choroidal artery. Interruption of this vessel causes a horizontal homonymous sector defect (wedgeshaped, D). Superior homonymous quadran tic defects ("piein the sky, " E) may result from a lesion along i\-Ieyer's loop (after temporal lobectomy) or along the inferior bank of the calcarine fissure . The anterior chiasm or junctional syndrome results in a unilateral optic nerve defect of one eye and a superior temporal defect in the other eye (A) due to the loop made by the inferonasal retina of the other eye (\Villebrand's knee). Lesions located in the most anterior portion of the calcarine cortex cause a crescent-shaped defect restricted to the temporal field of the contralateral eye (monocular temporal crescent, C). This is the only retrochiasmatic lesion that may result in a strictly unilateral visual field defect (Bralis, pp. 132-140).

Answer 183

A ## Footnote Occlusion of the anterior choroidal artery causes a homonymous defect in the upper and lower quadrants, with sparing of the horizontal sector (quadruple sectoranopia, B), which is usually characteristic of a lateral geniculate body infarct that is supplied by the anterior choroidal artery. The central portion of the lateral geniculate body receives blood flow primarily from the lateral posterior choroidal artery. Interruption of this vessel causes a horizontal homonymous sector defect (wedgeshaped, D). Superior homonymous quadran tic defects ("piein the sky, " E) may result from a lesion along i\-Ieyer's loop (after temporal lobectomy) or along the inferior bank of the calcarine fissure . The anterior chiasm or junctional syndrome results in a unilateral optic nerve defect of one eye and a superior temporal defect in the other eye (A) due to the loop made by the inferonasal retina of the other eye (\Villebrand's knee). Lesions located in the most anterior portion of the calcarine cortex cause a crescent-shaped defect restricted to the temporal field of the contralateral eye (monocular temporal crescent, C). This is the only retrochiasmatic lesion that may result in a strictly unilateral visual field defect (Bralis, pp. 132-140).

Answer 184

C ## Footnote Occlusion of the anterior choroidal artery causes a homonymous defect in the upper and lower quadrants, with sparing of the horizontal sector (quadruple sectoranopia, B), which is usually characteristic of a lateral geniculate body infarct that is supplied by the anterior choroidal artery. The central portion of the lateral geniculate body receives blood flow primarily from the lateral posterior choroidal artery. Interruption of this vessel causes a horizontal homonymous sector defect (wedgeshaped, D). Superior homonymous quadran tic defects ("piein the sky, " E) may result from a lesion along i\-Ieyer's loop (after temporal lobectomy) or along the inferior bank of the calcarine fissure . The anterior chiasm or junctional syndrome results in a unilateral optic nerve defect of one eye and a superior temporal defect in the other eye (A) due to the loop made by the inferonasal retina of the other eye (\Villebrand's knee). Lesions located in the most anterior portion of the calcarine cortex cause a crescent-shaped defect restricted to the temporal field of the contralateral eye (monocular temporal crescent, C). This is the only retrochiasmatic lesion that may result in a strictly unilateral visual field defect (Bralis, pp. 132-140).

Answer 185

B ## Footnote Occlusion of the anterior choroidal artery causes a homonymous defect in the upper and lower quadrants, with sparing of the horizontal sector (quadruple sectoranopia, B), which is usually characteristic of a lateral geniculate body infarct that is supplied by the anterior choroidal artery. The central portion of the lateral geniculate body receives blood flow primarily from the lateral posterior choroidal artery. Interruption of this vessel causes a horizontal homonymous sector defect (wedgeshaped, D). Superior homonymous quadran tic defects ("piein the sky, " E) may result from a lesion along i\-Ieyer's loop (after temporal lobectomy) or along the inferior bank of the calcarine fissure . The anterior chiasm or junctional syndrome results in a unilateral optic nerve defect of one eye and a superior temporal defect in the other eye (A) due to the loop made by the inferonasal retina of the other eye (\Villebrand's knee). Lesions located in the most anterior portion of the calcarine cortex cause a crescent-shaped defect restricted to the temporal field of the contralateral eye (monocular temporal crescent, C). This is the only retrochiasmatic lesion that may result in a strictly unilateral visual field defect (Bralis, pp. 132-140).

Answer 186

A. 1, 2, and 3 are correct **B. 1 and 3 are correct** C. 2 and 4 are correct D. Only 4 is correct E. All of the above ## Footnote The musculocutaneous nerve innervates the biceps, brachialis, and coracobrachialis muscles, which control elbow flexion and forearm supination (Bralis, p. 60).

Answer 187

A. Ventrolateral pons B. Basis pontis C. Posterior internal capsule **D. Cervicomeclullary junction ** E. Ventral lateral pons ## Footnote Where the pyramidal tract decussates at the cervicomedullary junction with segregation of arm fibers (rostral) and leg fibers (caudal), a lesion can cause the unique COI11- bination of ipsilateral arm weakness and contralateral leg paresis (cruciate paralysis) (Bralis, p. 95; Greenberg, p. 95).

Answer 188

A. j\lobar holoprosencephaly B. Lobar holoprosencephaly **C. Hydranencephaly ** D. Severe hydrocephalus E * . Anencephaly ## Footnote Hydranencephaly describes a brain replaced by CSF rather than compressed by expansion of the ventricles, as in severe hydrocephalus. Moreover, with severe hydrocephalus, there is usually a thin mantle of brain, which is absent in hydranencephaly. The absel1ce of a cortical mantle with hydranencephaly is most often associated with angiographic evidence of supra clinoid occlusion of the carotid arteries, which strongly suggests a vascular pathogenesis. The posterior fossa and thalami are often preserved due to preserved posterior circulation. The craniulll of afilicted children usually fails to grow and remains small. The incidence is estimated to be 1 in 6000, and affected infants rarely live longer than a yea r (Albright, pp. 155- 156).

Answer 189

A. Obstl'l1ctive hydrocephalus B. Failure of disjunction **C. Disorder of cellular migration ** D. Bilateral in utero disl'l1ption of the anterior circulation E. Failure of neural tube closure ## Footnote Hydranencephaly describes a brain replaced by CSF rather than compressed by expansion of the ventricles, as in severe hydrocephalus. Moreover, with severe hydrocephalus, there is usually a thin mantle of brain, which is absent in hydranencephaly. The absel1ce of a cortical mantle with hydranencephaly is most often associated with angiographic evidence of supra clinoid occlusion of the carotid arteries, which strongly suggests a vascular pathogenesis. The posterior fossa and thalami are often preserved due to preserved posterior circulation. The craniulll of afilicted children usually fails to grow and remains small. The incidence is estimated to be 1 in 6000, and affected infants rarely live longer than a yea r (Albright, pp. 155- 156).

Answer 190

A. Greater than 10 mL of gross blood is aspirated from the abdomen B. Microscopic evaluation of fluid aspirate reveals > 100,000hllmJ of red blood cells C. Greater than 500/m111.1 white blood cells D. Presence of bile or particulate matter in aspirate **E. An amylase level that is less than the normal Sel'l1111 level** ## Footnote DPL is considered positive if greater than 10 mL of gross blood is aspirated from the peritoneal cavity or if 1 L of lactated Ringer's solution is infused into the peritoneal cavity and microscopic evaluation reveals red blood cells > 100,000/ml11'\ white blood cells> 500/ml11'\ or the presence of bile, particulate matter, or amylase greater than the normal serum value. It can be used for penetrating stab wounds after positive local exploration or suspected hollow viscus injury, following an abnormal ultrasound examination, or following a normal ultrasound when the patient exhibits hemodynamic instability or signs and symptoms suggestive of an intra-abdominal injury (Nwariaku, pp. 64-65).

Answer 191

**A. Gemistocytic astrocytoma ** B. I-Iemangioblastoma C. Chordoma D. Clear cell meningioma E. Desmoplastic medulloblastoma ## Footnote Note the large, glassy eosinophilic cell bodies with an angular shape on this photomicrograph, which depicts a gemistocytic astrocytoma (Ellison, p. 627; WHO, p. 25).

Answer 192

A. Weber lateralizes to the left, Rinne is negative (b > a), Schwa bach test is normal B. Weber lateralizes to the right, Rinne is positive (a > b), Schwa bach test is normal **C. Weber lateralizes to the right, Rinne is negative, Schwa bach test is normal or slightly prolonged ** D. Weber lateralizes to the right, Rinne is positive, Schwa bach test is abnormal E. Weber lateralizes to the left, Rinne is positive, Schwa bach test is abnormal ## Footnote In conductive hearing loss on the right, the Weber test lateralizes to the right, the Rinne test is negative (bone conduction is better than air conduction), and the Schwabach test is normal or prolonged (the patient can hear the tuning fork longer than the examiner can) (Brazis, pp. 298-299)

Answer 193

A. Latency of appearance of nystagmus of 2 to 12 seconds B. The vertigo and nystagmus usually disappear 10 to 15 seconds after their appearance **C. Change in direction of nystagmus with the head down and persistence of nystagmus ** D. Habituation of the response with repeated maneuvers E. The reproducibility of abnormalities noted with this maneuver becomes inconsistent ## Footnote With peripheral lesions, severe rotational vertigo associated with nausea and vomiting and nystagmus appear approximately 2 to 15 seconds after performing the NylenBarany maneuver. There is usually habituation of response with repeated maneuvers, and the reproducibility of abnormalities wi th this maneuver becomes inconsistent with repeated testing. Cochlear and other neurologic symptoms are usually absent. The vertigo and nystagmus typically resolve within 10 to 15 seconds after their appearance; after the patient is rapidly brought bacl, to a sitting position, vertigo recurs and nystagmus develops in the opposite direction (Brazis, pp. 305- 306).

Answer 194

A. Creutzfeldt-Jakob disease B. Herpes encephalitis **C. Malaria ** D. Ganglioglioma E. Lymphoma ## Footnote Note the occlusion of the blood vessel, which is due to the presence of many ghost-like red blood cells that contain parasites on this I-I & E section depicting malaria. Patients with this disease can present with seizures, headache, somnolence, confUSion, photophobia, and almost any focal neurologic deficit. Without urgent treatment, these patients usually progress to coma and brain death (Ellison, pp. 653- 656).

Answer 195

A. Castleman's syndrome **B. Tuberous sclerosis ** C. Temporal lobe epilepsy D. Cafe aulait spots E. Cobblestone skin pattern ## Footnote This photomicrograph depicts a subependymal giant cell astrocytoma. This lesion is usually located adjacent to the foramen of ~\'Ionro and is associated with tuberous sclerosis (dominant mutation in TSC 1 on 9p or TSC 2 on 16p). It usually resembles gemistocytic astrocytoma, but is not infiltrative. Note the abundant cytoplasm, abundant perivascular fibrillar zone, and prominent nucleolus in this section. The nuclei are eccentric, which distinguishes this from gemistocytic astrocytoma (Ell ison, pp. 637-639).

Answer 196

**A. Hydrocephalus ** B. A 3-cmmeningioma of the falx C. Pituitary adenoma D. Temporal lobe porencephalic cyst E. Occipital lobe arterial-venous malformation ## Footnote This constellation of clinical findings is most consistent with Parinaud's syndrome, which is often associated with pineal region masses causing direct compression of the tectal pia te or from compression of the mesencephalic tectum by a dilated supra pineal recess in cases of hydrocephalus (Greenberg, p. 87)

Answer 197

A. Lies along the superior banlt of the lateral sulcus and extends posteriorly into the parietal lobe B. Representation of body parts is in the reverse sequence to that found in the primary somesthetic area with the two face areas adjacent C. Representation of the body is bilateral in SII, although contralateral predominates D. The efferent cortical projections are mainly to SI and the primary motor cortex **E. Lesions typically cause contralateral weakness ** ## Footnote SII lies along the superior bank of the lateral sulcus and extends posteriorly into the parietal lobe; it has repre sentation of body parts in the reverse sequence to that found in the primary somesthetic area , with the two face areas being adjacent. Representation of the body is bilateral in SII (although contralateral predominates), and the efferent cortical projections are mainly to SI and the primary motor cortex (Carpenter, pp. 404-405).

Answer 198

**A. Inability to name objects (kept from view) palpated by the right hand ** B. Inability to name objects presented to the left hemifield C. No interference with most activities of daily living D. Inability to copy a complex design with the right hand E. Unable to execute a command with the left hand ## Footnote The corpus callosum functions to transfer information from one hemisphere to the other. After sectioning, the patient cannot execute a command with the left hand but will do so consistently with the right. The left hemisphere understands the command but is unable to transfer that information to the right side of the brain. The right hemisphere does not typically understand the command because it lacks the ability to understand language . Therefore a patient presented with an object with the right hand should be able to reliably name it, since these fibers are relayed to the contralateral cerebral cortex (DeMyer, pp. 316, 319).

Answer 199

A. Pons, thalamus, putamen, cerebellum, lobar **B. Putamen, thalamus, pons, cerebellum, lobar ** C. Putamen , thalamus, cerebellum, pons, lobar D. Thalamus, putamen, cerebellum, lobar, pons E. Thalamus, putamen, cerebellum, pons, lobar ## Footnote The most common locations for hypertensive intracranial hemorrhage include the putamen, followed by the thalamus, pons, cerebellum, and lobar regions. The origin of some "hypertensive" putaminal hemorrhages are believed to result frommicroaneurysms of "Charcot-Bouchard," but this is somewhat controversial (Greenberg, p. 815).

Answer 200

A. Wide-based "magnetic" gait B. Bradyphrenia C. Incontinence **D. Headaches ** E. Transient increases in intracranial pressure with continuous monitoring ## Footnote Hydrocephalus, gait disturbance ("magnetic gait" with short, shuffling steps), dementia (primarily memory impairment with bradyphrenia or slowness of thought), incontinence, and transient elevations in intracranial pressure (with monitoring) may all occur with normal pressure hydrocephalus (NPH). Headache and papilledema are typically not seen in patients with NPH; their presence should raise suspicion of another diagnosis (Greenberg, pp. 191- 194)

Answer 201

**A. Right frontal tumor** B. Left occipital tumor C. Uremia D. Sleep E. Large hemispheric insult ## Footnote The seizure spikes are over a fairly wide area of the right parasagittal region (ma.ximal F4, C4) consistent with a right frontal onset corresponding with a right parasagittal meningioma. In order to localize seizure foci, it is imperative for clinicians to memorize standard electrode placement and designations. Note that by convention, electrodes designated with odd numbers are on the left, while with even numbers on the right. The standard electrode designations are as follows: Fpl/Fp2 = frontopolar or prefrontal; F3/F4 = midfrontal; C3/C4 = central (roughly over central sulcus); P3/P4 = parietal; 01/02 = OCCipital; F7/F8 = inferior frontal (sometimes called anterior frontal); T3/T4 = mid temporal (records activity over anterior and midtemporal activity, important for temporal lobe epilepsy); 1'5/1'6 = posterior temporal; Fz, Cz, pz = midline electrodes in frontal and parietal regions (record mesial surfaces of hemispheres); AlIA2 = ear reference electrodes (while used for references also record mid temporal activity); TI/T2 = so-called true anterior temporal electrodes; Spl/Sp2 = sphenoidal electrodes (record activity from inferomesial surface of the temporal lobes) (Rowan, pp. 4- 7).

Answer 202

D ## Footnote Fibers of the ansa lenticularis (D) leave the outer part of the medial globus pallidus, pass around the internal capsule, and enter the prerubral field (field H of Forel, not labeled) prior to merging with the lenticular fasciculus (H2). Fibers of the lenticular fasciculus originate from the inner part of the medial globus pallidus, traverse the posterior limb of the anterior capsule, and pass medially, dorsal to the subthalamic nucleus, to also enter the prerubral field. The ansa lenticularis and lenticular fasciculus then travel together dorsal to the zona incerta as components of the thalamic fasciculus (A). The subthalamic fasciculus (C) is comprised of pallidosubthalamic fibers originating from the lateral or external pallidal segment and subthalamopallidal fibers that terminate in the medullary lamina of both pallidal segments. Both components of the subthalamic fasciculus cross the internal capsule. Thalamostriate fibers from the centromedian nucleus project to the putamen (E) (Carpenter, pp. 337- 345).

Answer 203

E ## Footnote Fibers of the ansa lenticularis (D) leave the outer part of the medial globus pallidus, pass around the internal capsule, and enter the prerubral field (field H of Forel, not labeled) prior to merging with the lenticular fasciculus (H2). Fibers of the lenticular fasciculus originate from the inner part of the medial globus pallidus, traverse the posterior limb of the anterior capsule, and pass medially, dorsal to the subthalamic nucleus, to also enter the prerubral field. The ansa lenticularis and lenticular fasciculus then travel together dorsal to the zona incerta as components of the thalamic fasciculus (A). The subthalamic fasciculus (C) is comprised of pallidosubthalamic fibers originating from the lateral or external pallidal segment and subthalamopallidal fibers that terminate in the medullary lamina of both pallidal segments. Both components of the subthalamic fasciculus cross the internal capsule. Thalamostriate fibers from the centromedian nucleus project to the putamen (E) (Carpenter, pp. 337- 345).

Answer 204

F ## Footnote Fibers of the ansa lenticularis (D) leave the outer part of the medial globus pallidus, pass around the internal capsule, and enter the prerubral field (field H of Forel, not labeled) prior to merging with the lenticular fasciculus (H2). Fibers of the lenticular fasciculus originate from the inner part of the medial globus pallidus, traverse the posterior limb of the anterior capsule, and pass medially, dorsal to the subthalamic nucleus, to also enter the prerubral field. The ansa lenticularis and lenticular fasciculus then travel together dorsal to the zona incerta as components of the thalamic fasciculus (A). The subthalamic fasciculus (C) is comprised of pallidosubthalamic fibers originating from the lateral or external pallidal segment and subthalamopallidal fibers that terminate in the medullary lamina of both pallidal segments. Both components of the subthalamic fasciculus cross the internal capsule. Thalamostriate fibers from the centromedian nucleus project to the putamen (E) (Carpenter, pp. 337- 345).

Answer 205

C ## Footnote Fibers of the ansa lenticularis (D) leave the outer part of the medial globus pallidus, pass around the internal capsule, and enter the prerubral field (field H of Forel, not labeled) prior to merging with the lenticular fasciculus (H2). Fibers of the lenticular fasciculus originate from the inner part of the medial globus pallidus, traverse the posterior limb of the anterior capsule, and pass medially, dorsal to the subthalamic nucleus, to also enter the prerubral field. The ansa lenticularis and lenticular fasciculus then travel together dorsal to the zona incerta as components of the thalamic fasciculus (A). The subthalamic fasciculus (C) is comprised of pallidosubthalamic fibers originating from the lateral or external pallidal segment and subthalamopallidal fibers that terminate in the medullary lamina of both pallidal segments. Both components of the subthalamic fasciculus cross the internal capsule. Thalamostriate fibers from the centromedian nucleus project to the putamen (E) (Carpenter, pp. 337- 345).

Answer 206

A ## Footnote Fibers of the ansa lenticularis (D) leave the outer part of the medial globus pallidus, pass around the internal capsule, and enter the prerubral field (field H of Forel, not labeled) prior to merging with the lenticular fasciculus (H2). Fibers of the lenticular fasciculus originate from the inner part of the medial globus pallidus, traverse the posterior limb of the anterior capsule, and pass medially, dorsal to the subthalamic nucleus, to also enter the prerubral field. The ansa lenticularis and lenticular fasciculus then travel together dorsal to the zona incerta as components of the thalamic fasciculus (A). The subthalamic fasciculus (C) is comprised of pallidosubthalamic fibers originating from the lateral or external pallidal segment and subthalamopallidal fibers that terminate in the medullary lamina of both pallidal segments. Both components of the subthalamic fasciculus cross the internal capsule. Thalamostriate fibers from the centromedian nucleus project to the putamen (E) (Carpenter, pp. 337- 345).

Answer 207

B ## Footnote Fibers of the ansa lenticularis (D) leave the outer part of the medial globus pallidus, pass around the internal capsule, and enter the prerubral field (field H of Forel, not labeled) prior to merging with the lenticular fasciculus (H2). Fibers of the lenticular fasciculus originate from the inner part of the medial globus pallidus, traverse the posterior limb of the anterior capsule, and pass medially, dorsal to the subthalamic nucleus, to also enter the prerubral field. The ansa lenticularis and lenticular fasciculus then travel together dorsal to the zona incerta as components of the thalamic fasciculus (A). The subthalamic fasciculus (C) is comprised of pallidosubthalamic fibers originating from the lateral or external pallidal segment and subthalamopallidal fibers that terminate in the medullary lamina of both pallidal segments. Both components of the subthalamic fasciculus cross the internal capsule. Thalamostriate fibers from the centromedian nucleus project to the putamen (E) (Carpenter, pp. 337- 345).

Answer 208

A. Leukemia B. Lymphoma **C. Epidural abscess ** D. Epidural lipomatosis E. IIemangioblastoma ## Footnote Note the prominent ring enhancement of this spinal epidural abscess, with compression of the adjacent spinal cord . The most lil{ely causative organism in a patient with a history of intravenous drug abuse is Staph. aU1"eliS (Ramsey, pp.498- 502)

Answer 209

A. 1,2, and 3 are correct **B. 1 and 3 are correct ** C. 2 and 4 are correct D. Only 4 is correct E. All of the above ## Footnote Necrotizing wound infections are produced by Clostridiwn and ~-hemolytic streptococcal species. Unlike other wound infections that may appear a few days to 1 week after surgery, necrotizing infections are evident in the first few postoperative days; they are characterized by skin crepitance and fluid-filled bullae. Spread to deeper tissues is a major concern, as this may result in rhabdomyolysis and myoglobinuric renal failure (Marino, p. 489).

Answer 210

A. Tentorial artery (of Bernasconi and Cassinari) B. Dorsal meningeal artery C. Inferior hypophyseal artery **D. Vidian artery ** E. McConnell's capsular artery ## Footnote There are three main branches that originate from the intracavernous portion of the ICA: the meningohypophyseal trunk, the artery of the inferior cavernous sinus, and the artery of McConnell. The meningohypophyseal trunk trifurcates into the tentorial artery (of Bernasconi and Cassinari), the dorsal meningeal artery (supplies dura over dorsum sellae), and the inferior hypophyseal artery, which supplies the posterior pituitary gland and sellar floor. !vlcConnell's artery runs along the dura covering the sellar floor to supply the anterior pituitary gland, while the artery of the inferior cavernous sinus provides blood supply to the third, fourth , and sixth cranial nerves as well as the gasserian ganglion and cavernous sinus dura. The vidian artery originates from the petrous lCA (Osborn DCA, pp. 86- 87).

Answer 211

**A. Suprascapular ** B. Axillary C. Spinal accessory D. Posterior interosseous E. Dorsal scapula ## Footnote Patients with entrapment or trauma to the suprascapular nerve often complain of shoulder pain centered over the lateral scapula and posterior shoulder, which is most often aggravated by arm abduction during the first 15 degrees (supraspinatus muscle) and external arm rotation when the elbow is fl exed at 90 degrees (infraspinatus muscle). Atrophy of the supraspinatus and infraspinatus muscles may also be apparent on inspection . EMG reveals dene rvation potentials in the supraspinatus and infraspinatus [uuscles and is the best diagnostic test. Conservative treatment measures include shoulder exercises and local injections of steroids and analgesics. Operative decompression usually includes sectioning of the suprascapular ligament (Youmans, pp. 3932- 3933)

Answer 212

A. Aspirin decreases the amount of PDGF secreted by tumor cells B. Aspirin decreases prostaglandin synthesis in fibroblasts adjacent to the tumor **C. Aspirin halts the production of prostaglandin by the tUlllor cells ** D. Aspirin decreases the amount of substance P in the dorsal horn of spinal cord cells E. Aspirin significantly reduces prostaglandin synthesis in the vasculature supplying the lesion ## Footnote Patients with osteoid osteoma involving the lumbar spine typically present with back pain that is exacerbated at night. This condition is believed to result fr0111 prostaglandin production by the tumor. Aspirin has classically been shown to relieve the pain (Youmans, p. 4297).

Answer 213

A. Anatomic hemispherectomy B. Functional hemispherectomy **C. Sectioning of the corpus callosum ** D. Multiple subpial transection E. Depth electrode placement for monitoring ## Footnote Atonic seizures, also called "drop attacl{s," are characterized by total loss of muscle tone. When they are preceded by a brief myoclonic seizure or tonic spasm, an acceleratory force is added to the fall, furth er contributing to the high rate of self-injury with this type of seizure. Most patients referred for corpus callosotomy have severe, medically refractory seizures usually accompanied by mental retardation and a severely abnormal EEG. UnW,e lesionectomy, corpus callosotomy is palliative, not curative. Nevertheless, thjs procedure can be highly effective for generalized seizures, with 80% of patients experiencing complete or nearly comple te cessation of atonic , tonic, and tonic-clonic attacks in some reports (Merritt, pp. 814, 827).

Answer 214

A. A:'(illary nerve injury B. Suprascapular nerve injury C. Dorsal scapular nerve injury **D. Spinal accessory nerve injury ** E. Brachial plexopathy ## Footnote Atonic seizures, also called "drop attacl{s," are characterized by total loss of muscle tone. When they are preceded by a brief myoclonic seizure or tonic spasm, an acceleratory force is added to the fall, furth er contributing to the high rate of self-injury with this type of seizure. Most patients referred for corpus callosotomy have severe, medically refractory seizures usually accompanied by mental retardation and a severely abnormal EEG. UnW,e lesionectomy, corpus callosotomy is palliative, not curative. Nevertheless, thjs procedure can be highly effective for generalized seizures, with 80% of patients experiencing complete or nearly comple te cessation of atonic , tonic, and tonic-clonic attacks in some reports (Merritt, pp. 814, 827).

Answer 215

A. 1,2, and 3 are correct **B. 1 and 3 are correct ** C. 2 and4 are correct D. Only 4 is correct E. All of the above ## Footnote Atonic seizures, also called "drop attacl{s," are characterized by total loss of muscle tone. When they are preceded by a brief myoclonic seizure or tonic spasm, an acceleratory force is added to the fall, furth er contributing to the high rate of self-injury with this type of seizure. Most patients referred for corpus callosotomy have severe, medically refractory seizures usually accompanied by mental retardation and a severely abnormal EEG. UnW,e lesionectomy, corpus callosotomy is palliative, not curative. Nevertheless, thjs procedure can be highly effective for generalized seizures, with 80% of patients experiencing complete or nearly comple te cessation of atonic , tonic, and tonic-clonic attacks in some reports (Merritt, pp. 814, 827).

Answer 216

A. MEG provides better spatial and temporal resolution for localization of cortical neuronal activity B. Mass lesions or other pathologic changes do not significantly distort the signal detected by MEG C. MEG signa ls are not as readily attenuated as compared to EEG signals D. MEG includes data points from below the surface, whereas EEG reflects only the cortical surface **E. MEG includes both a tangential and radial component of neuronal current, whereas EEG includes only a tangential component, which significantly reduces the complexity of the signal ** ## Footnote MEG has several advantages over EEG recording. First, unlil{e EEG-based techniques, which measure electrical potentials mainly from extracellular volume currents, the magnetic fields measured with MEG primarily refl ec t intracellular current flow and are not attenuated by the inhomogeneously conducting layers of bone, scalp, and other extracerebral tissue . This provides excellent spatial and temporal resolution for localization of neuronal activity, and it more accurately represents the localization of eloquent cortex than EEG. Second, mass lesions or other pathologic changes in the brain, which may significantly distort the signal detected

Answer 217

A. Sphenoid wing meningioma B. Chondrosarcoma **C. Fibrous dysplasia** D. Esthenioblastoma E. Osteochondroma ## Footnote Note the expansion of bone (sphenoid) and "ground glass appearance" on this noncontrasted CT scan in a patient with fibrous dysplasia. Malignant degeneration, usually to osteosarcoma, has been reported to occur in approximately 0.5% of patients with fibrous dysplasia (Albright, pp. 456- 457).

Answer 218

A. Osteochondroma B. Osteoblastoma C. Chloroma **D. Osteosarcoma ** E. Neuroblastoma ## Footnote Note the expansion of bone (sphenoid) and "ground glass appearance" on this noncontrasted CT scan in a patient with fibrous dysplasia. Malignant degeneration, usually to osteosarcoma, has been reported to occur in approximately 0.5% of patients with fibrous dysplasia (Albright, pp. 456- 457).

Answer 219

A. First B. Second **C. Third** D. Fourth E. Sixth ## Footnote The stylopharyngeus muscle is innervated by the glossopharyngeal nerve (IX) and is the only muscle derived from the third brachial arch . The muscles of facial expression are all innervated by the facial nerve (VII) and are derived from the second brachial arch, whereas the thyroarytenoid muscle and intrinsic laryngeal musculature (except cricothyroid muscle, fourth arch derivative) are derived from the sbah brachial arch. The muscles of mastication are derived from the first brachial arch and are innervated by the mandibular division of the trigeminal nerve (April, p. 556).

Answer 220

A. Atherosclerosis B. Malignant brain tumor C. Fibromuscular dysplasia **D. lvloyamoya disease ** E. Embolic infarct ## Footnote Note the paucity of blood flow in the distal internal carotid and cerebral artery vasculature and the presence of prominent collaterals that resemble a "puff of smoke" on this lateral angiogram, which depicts moyamoya (Albright, pp. 1053- 1069).

Answer 221

A. Rods and cones of the retina B. Bipolar cells **C. Ganglion cells ** D. Horizontal cells E. Amacrine cells ## Footnote The ganglion cells in the retina gives rise to the optic nerve. The ganglion cells receive impulses from the bipolar cells, which, in turn, receive signals from the light-sensitive rods and cones (Kandel, pp. 517 -521).

Answer 222

A. Neurotmesis B. A.'wnotmesis **C. Neurapraxia ** D. A and B E. None of the above ## Footnote With neurotmesis, there is complete anatomic transection of the nerve accompanied by Wallerian degeneration. These injuries almost always require surgical repair, although the timing remains unclear. For sharply divided nerves, immediate repair appears to be ideal, whereas for bluntly injured nerves, some advocate waiting approximately 3 to 4 weeks prior to intervening surgically to allow for better proximal and distal nerve stump delineation. With a:mnotmesis, there is a loss of axonal continuity, but the soma remains continuous. Wallerian degeneration also occurs with this type of insult. With neurapraxia, conduction ceases without structural damage to the nerve. There is a physiologic transection, which is often accompanied by defective axonal transport. This type of nerve injury frequently recovers by 6 to 8 weeks on average. Stimulating distal to a nerve lesion at about 1 week postinjury results in no action potentials if Wallerian degeneration occurs (Greenberg, p. 532; Youmans, pp. 3825- 3826).

Answer 223

A. Neurotmesis **B. A.'wnotmesis** C. Neurapraxia D. A and B E. None of the above ## Footnote With neurotmesis, there is complete anatomic transection of the nerve accompanied by Wallerian degeneration. These injuries almost always require surgical repair, although the timing remains unclear. For sharply divided nerves, immediate repair appears to be ideal, whereas for bluntly injured nerves, some advocate waiting approximately 3 to 4 weeks prior to intervening surgically to allow for better proximal and distal nerve stump delineation. With a:mnotmesis, there is a loss of axonal continuity, but the soma remains continuous. Wallerian degeneration also occurs with this type of insult. With neurapraxia, conduction ceases without structural damage to the nerve. There is a physiologic transection, which is often accompanied by defective axonal transport. This type of nerve injury frequently recovers by 6 to 8 weeks on average. Stimulating distal to a nerve lesion at about 1 week postinjury results in no action potentials if Wallerian degeneration occurs (Greenberg, p. 532; Youmans, pp. 3825- 3826).

Answer 224

A. Neurotmesis B. A.'wnotmesis C. Neurapraxia **D. A and B ** E. None of the above ## Footnote With neurotmesis, there is complete anatomic transection of the nerve accompanied by Wallerian degeneration. These injuries almost always require surgical repair, although the timing remains unclear. For sharply divided nerves, immediate repair appears to be ideal, whereas for bluntly injured nerves, some advocate waiting approximately 3 to 4 weeks prior to intervening surgically to allow for better proximal and distal nerve stump delineation. With a:mnotmesis, there is a loss of axonal continuity, but the soma remains continuous. Wallerian degeneration also occurs with this type of insult. With neurapraxia, conduction ceases without structural damage to the nerve. There is a physiologic transection, which is often accompanied by defective axonal transport. This type of nerve injury frequently recovers by 6 to 8 weeks on average. Stimulating distal to a nerve lesion at about 1 week postinjury results in no action potentials if Wallerian degeneration occurs (Greenberg, p. 532; Youmans, pp. 3825- 3826).

Answer 225

**A. Neurotmesis ** B. A.'wnotmesis C. Neurapraxia D. A and B E. None of the above ## Footnote With neurotmesis, there is complete anatomic transection of the nerve accompanied by Wallerian degeneration. These injuries almost always require surgical repair, although the timing remains unclear. For sharply divided nerves, immediate repair appears to be ideal, whereas for bluntly injured nerves, some advocate waiting approximately 3 to 4 weeks prior to intervening surgically to allow for better proximal and distal nerve stump delineation. With a:mnotmesis, there is a loss of axonal continuity, but the soma remains continuous. Wallerian degeneration also occurs with this type of insult. With neurapraxia, conduction ceases without structural damage to the nerve. There is a physiologic transection, which is often accompanied by defective axonal transport. This type of nerve injury frequently recovers by 6 to 8 weeks on average. Stimulating distal to a nerve lesion at about 1 week postinjury results in no action potentials if Wallerian degeneration occurs (Greenberg, p. 532; Youmans, pp. 3825- 3826).

Answer 226

A. Pseudoarthrosis B. Osteomyelitis **C. End-fusion degenerative changes ** D. Spondylolysis E. Subsidence ## Footnote The acquisition of bony spinal fusion increases motion and stress at adjacent Illation segments, which can accelerate degenerative changes. This process is further enhanced by failure to repair sagittal balance during surgery. Although not the ideal study to evaluate bony fUSion, this MRl does not demonstrate pseudoarthrosis at the prior fusion site, subsidence, basilar invagination , or osteomyelitis. It shows end-fusion degenerative changes and loss of the normal lordotic curve of the cervical spine, which may be contributing to this patients' new clinical problems (Benzel, p.130).

Answer 227

B ## Footnote This diagram shows the structures that traverse the internal auditory canal (lAC). The facial nerve (A) and nervus intermedius are separated from the superior vestibular nerve by a vertical crest of bone known as Bill's bar (F). Bill's bar arises from the transverse crest (G) within the lateral aspect of the lAC. The cochlear nerve (C) and inferior vestibular nerve enter the lAC inferior to the transverse crest, as depicted in the diagram (Will

Answer 228

C ## Footnote This diagram shows the structures that traverse the internal auditory canal (lAC). The facial nerve (A) and nervus intermedius are separated from the superior vestibular nerve by a vertical crest of bone known as Bill's bar (F). Bill's bar arises from the transverse crest (G) within the lateral aspect of the lAC. The cochlear nerve (C) and inferior vestibular nerve enter the lAC inferior to the transverse crest, as depicted in the diagram (Will

Answer 229

D ## Footnote This diagram shows the structures that traverse the internal auditory canal (lAC). The facial nerve (A) and nervus intermedius are separated from the superior vestibular nerve by a vertical crest of bone known as Bill's bar (F). Bill's bar arises from the transverse crest (G) within the lateral aspect of the lAC. The cochlear nerve (C) and inferior vestibular nerve enter the lAC inferior to the transverse crest, as depicted in the diagram (Will

Answer 230

A ## Footnote This diagram shows the structures that traverse the internal auditory canal (lAC). The facial nerve (A) and nervus intermedius are separated from the superior vestibular nerve by a vertical crest of bone known as Bill's bar (F). Bill's bar arises from the transverse crest (G) within the lateral aspect of the lAC. The cochlear nerve (C) and inferior vestibular nerve enter the lAC inferior to the transverse crest, as depicted in the diagram (Will

Answer 231

E ## Footnote This diagram shows the structures that traverse the internal auditory canal (lAC). The facial nerve (A) and nervus intermedius are separated from the superior vestibular nerve by a vertical crest of bone known as Bill's bar (F). Bill's bar arises from the transverse crest (G) within the lateral aspect of the lAC. The cochlear nerve (C) and inferior vestibular nerve enter the lAC inferior to the transverse crest, as depicted in the diagram (Will

Answer 232

F ## Footnote This diagram shows the structures that traverse the internal auditory canal (lAC). The facial nerve (A) and nervus intermedius are separated from the superior vestibular nerve by a vertical crest of bone known as Bill's bar (F). Bill's bar arises from the transverse crest (G) within the lateral aspect of the lAC. The cochlear nerve (C) and inferior vestibular nerve enter the lAC inferior to the transverse crest, as depicted in the diagram (Will

Answer 233

G ## Footnote This diagram shows the structures that traverse the internal auditory canal (lAC). The facial nerve (A) and nervus intermedius are separated from the superior vestibular nerve by a vertical crest of bone known as Bill's bar (F). Bill's bar arises from the transverse crest (G) within the lateral aspect of the lAC. The cochlear nerve (C) and inferior vestibular nerve enter the lAC inferior to the transverse crest, as depicted in the diagram (Will

Answer 234

**A. Disjunction ** B. Migration C. J'vIyelination D. Cleavage E. Transverse segmentation ## Footnote Three forms of lipomyelomeningocele have been described that have clinical relevance: dorsal, caudal (terminal), and transitional. They are believed to arise from faulty disjunction of the neuroectoderm from the overlying ectodenn, which leaves gaps between these two developing layers. Subsequently, mesenchymal cells are believed to ingress through these defective areas into the central canal, where they are induced to form a bulk of lipomatous tissue, which subsequently prevents fusion or complete closure of the neural tube.

Answer 235

A. Posterior B. Dorsola teral **C. Ven trola teral ** D. Dorsomedial E. Rostral ## Footnote Three forms of lipomyelomeningocele have been described that have clinical relevance: dorsal, caudal (terminal), and transitional. They are believed to arise from faulty disjunction of the neuroectoderm from the overlying ectodenn, which leaves gaps between these two developing layers. Subsequently, mesenchymal cells are believed to ingress through these defective areas into the central canal, where they are induced to form a bulk of lipomatous tissue, which subsequently prevents fusion or complete closure of the neural tube.

Answer 236

A. Ventromedial B. Dorsolateral **C. Dorsomedial ** D. Rostral E. Ventrolateral ## Footnote Three forms of lipomyelomeningocele have been described that have clinical relevance: dorsal, caudal (terminal), and transitional. They are believed to arise from faulty disjunction of the neuroectoderm from the overlying ectodenn, which leaves gaps between these two developing layers. Subsequently, mesenchymal cells are believed to ingress through these defective areas into the central canal, where they are induced to form a bulk of lipomatous tissue, which subsequently prevents fusion or complete closure of the neural tube.

Answer 237

A. 1,2, and 3 are correct **B. 1 and 3 are correct ** C. 2 and 4 are correct D. Only 4 is correct E. All of the above ## Footnote The ethmoid bone (vertical plate) and vomer contribute to the anterosuperior and posteroinferior portions of the nasal septum, respectively. The nasal bones and nasal crests of the frontal bones mal{e smaller contributions (Moore, p. 945)

Answer 238

A. Arbovirus B. Myxovirus **C. Ente rovirus ** D. Arenavirus E. Togavirus ## Footnote Viral infections of the CNS can result in meningitis, ventriculitis, encephalitis, and myelitis. CSF in patients with viral syndromes of the CNS reveals increased pressure, lymphocytic pleocytosis, mild elevations in protein, and normal glucose levels. Viral (aseptic) meningitis usually peaks in the summer and fall seasons, whereas bacterial meningitis is more common during the winter. The most cOlllmon causes of viral meningitis are the enteroviruses, but togaviruses are also frequent pathogens. Encephalitis often results from infections with herpes simplex virus, mumps, or arboviruses (Merritt, pp. 134-138).

Answer 239

A. Stage 1 B. Stage 3 C. Stage 4 D. REM **E. Band C ** ## Footnote Night terrors most commonly occur during stages 3 and 4 of deep sleep. During a night terror, the child appears extremely frightened and agitated and, although seemingly awake , is actually in deep sleep (stage 3 or 4) and is difficult to rouse. Upon awakening, the child has no apparent memory of the event. Although concerning to parents, night

Answer 240

A. Lymphoma B. Squamous cell carcinoma **C. Esthesioneuroblastoma ** D. Adenocarcinoma E. Rl1abdomyosarcoma ## Footnote The clinical history of this patient and destructive MRI appearance of tIllS lesion are highly suggestive of a malignant neoplasm involVing the paranasal sinuses. The histologic and immunohistochemical markers are most consistent with esthesioneuroblastoma (Kaye and Laws, pp. 885- 889).

Answer 241

A. Pon tine tegmentulll B. Dorelio's canal C. Prepontine cistern **D. Cave rnous sinus ** E. Region of the ligament of GrUber ## Footnote Sympathetic nervous system fibers (traveling with the internal carotid artery) and cranial nerve VI are in close proximity in the cavernous sinus. Tumors or other lesions in this location may produce oculosympathetic paralysis (without anhidrosis) (Brazis, p. 265).

Answer 242

A. Paramedian pontine reticular formation (PPRF) **B. Rostral interstitial nucleus of the medial longitudinal fasciculus (MLF) ** C. Rostral interstitial nucleus of Cajal D. Nucleus of Roller E. Nucleus of Collier ## Footnote Vertical and torsional saccadic eye movements are generated by the rostral interstitial nucleus of the MLF (rLMLF), located in the prerubral field of the ventral diencephalomesencephalic junction, rostral to the tractus retroflexus and ventral to the nucleus of Darkschewitsch. Although cells involved with downward saccades are different from the ones involved with upward saccades, they are dispersed throughout the riMLF without separation of upward and downward pools (Brazis, pp. 199- 200).

Answer 243

**A. Anterior ** B. Posterior C. Medial D. Lateral E. Anterior and lateral F. Inferior and medial G. Posterior and medial H. None of the above

Answer 244

A. Anterior B. Posterior C. Medial **D. Lateral ** E. Anterior and lateral F. Inferior and medial G. Posterior and medial H. None of the above

Answer 245

A. Anterior B. Posterior C. Medial D. Lateral E. Anterior and lateral F. Inferior and medial **G. Posterior and medial ** H. None of the above

Answer 246

**A. Anterior ** B. Posterior C. Medial D. Lateral E. Anterior and lateral F. Inferior and medial G. Posterior and medial H. None of the above

Answer 247

A. Anterior B. Posterior C. Medial D. Lateral E. Anterior and lateral **F. Inferior and medial ** G. Posterior and medial H. None of the above

Answer 248

A. Anterior B. Posterior C. Medial **D. Lateral ** E. Anterior and lateral F. Inferior and medial G. Posterior and medial H. None of the above

Answer 249

A. Anterior B. Posterior C. Medial D. Lateral E. Anterior and lateral F. Inferior and medial G. Posterior and medial **H. None of the above**

Answer 250

A. Anterior B. Posterior **C. Medial ** D. Lateral E. Anterior and lateral F. Inferior and medial G. Posterior and medial H. None of the above

Answer 251

A. Anterior B. Posterior C. Medial D. Lateral **E. Anterior and lateral ** F. Inferior and medial G. Posterior and medial H. None of the above

Answer 252

A. Anterior **B. Posterior ** C. Medial D. Lateral E. Anterior and lateral F. Inferior and medial G. Posterior and medial H. None of the above

Answer 253

A. Atrophic muscle fibers B. Angular fibers C. Eosinophilic infiltration D. Target cells **E. Type-specific grouping of muscle fibers** ## Footnote Denervation typically causes atrophy of muscle fibers, which eventually become angulated, as well as the formation of distinctive fibers with three unique zones often referred to as "target cells. " Reinnervation is characterized by type-specific grouping of fibers, which is in contrast to the mixed, "ch eckerboard" pattern of types 1 and 2 skeletal fibers and the atrophic, angulated cells of denervated fibers. Eosinophils in muscle cells are often seen with parasitic infections (Merritt, p. 736).

Answer 254

**A. Tuberculosis ** B. Chronic infarct C. Multiple sclerosis D. Histoplasmosis E. Pilocytic astrocytoma ## Footnote Within this tuberculoma, note the prominent region of caseating necrosis (left), in which no cellular detail can be ascertained. A peripheral rim of lymphocytes and a fibrous capsule surround the granuloma, and an occasional histiocyte is observed (Ellison, pp. 339- 342).

Answer 255

A. Neurocysticercosis B. Third ventricular tumor **C. Metastatic disease ** D. Toxoplasmosis E. Multiple sclerosis ## Footnote Note the multiple lesions at the gray-white junction, which is most consistent with metastatic disease (Ellison, pp.743-750).

Answer 256

A. 1,2, and 3 are correct B. 1 and 3 are correct C. 2 and 4 are correct **D. Only 4 is correct ** E. All of the above ## Footnote The right and left posterior cricoarytenoid muscles abduct the vocal cords (Moore, p. 1060).

Answer 257

**A. Left beating nystagmus ** B. Eye deviation to the left C. Right beating nystagmus D. Convergence retraction nystagmus E. WEEINO response ## Footnote Injecting cold water into the right ear causes the endolymph to move away from the ampulla of the horizontal canal. This causes a decreased tone of input into the left abducens nucleus, which results in slow conjugate eye movements toward the right due to right lateral rectus and left medial rectus contraction. Subsequently, there will be compensatory fast eye movements (left-beating nystagmus) to the left. Warm water injected into the right ear will produce the opposite response. The mnemonic COWS (cold opposite; warm same) helps define the fast phase of eye movements during caloric testing (Kline, pp. 57- 59).

Answer 258

A. Dilute (1/8%) pilocarpine B. 1% Hydroxyamphetamine **C. 10% Cocaine ** D. Atropine E. Dilute epinephrine (1:1000)

Answer 259

A. Dilute (1/8%) pilocarpine **B. 1% Hydroxyamphetamine ** C. 10% Cocaine D. Atropine E. Dilute epinephrine (1:1000)

Answer 260

A. Dilute (1/8%) pilocarpine B. 1% Hydroxyamphetamine C. 10% Cocaine **D. Atropine ** E. Dilute epinephrine (1:1000)

Answer 261

A. Dilute (1/8%) pilocarpine B. 1% Hydroxyamphetamine C. 10% Cocaine **D. Atropine ** E. Dilute epinephrine (1:1000)

Answer 262

**A. Dilute (1/8%) pilocarpine ** B. 1% Hydroxyamphetamine C. 10% Cocaine D. Atropine E. Dilute epinephrine (1:1000)

Answer 263

A. B-mocle ultrasonography **B. Doppler ultrasonography** C. Both D. None of the above ## Footnote Brightness modulation ultrasonography (B mode), based on reflection of sound waves off tissue interfaces, is better used to view anatomic detail and can be used to measure blood vessel diameter and evaluate plaques. It typically shows the carotid system as a pulsatile luminal structure, with a thin echogenic line representing the intimal surface. The basic principle underlying this mode of imaging is the variable impedance that different body tissues naturally possess. Doppler shift ultrasonography is based on the reflection of sound waves off moving targets such as red blood cells. It is better for evaluating flow dynamics such as blood velocity, which typically increases in segments of stenosis. Although the combination of B-mode and Doppler ultrasonography improved the ability to localize the source of the reflected signal when it was involved with complicated blood velocity patterns (vasospasm, atherosclerosis), the signal was still quit difficult to interpret. lI'IOl'e recently, through the use of fast Fourier transformations, the complex signal was separated into a number of single-frequency components, which made it easier to interpret. These technologies were later integrated,

Answer 264

A. B-mocle ultrasonography **B. Doppler ultrasonography ** C. Both D. None of the above ## Footnote Brightness modulation ultrasonography (B mode), based on reflection of sound waves off tissue interfaces, is better used to view anatomic detail and can be used to measure blood vessel diameter and evaluate plaques. It typically shows the carotid system as a pulsatile luminal structure, with a thin echogenic line representing the intimal surface. The basic principle underlying this mode of imaging is the variable impedance that different body tissues naturally possess. Doppler shift ultrasonography is based on the reflection of sound waves off moving targets such as red blood cells. It is better for evaluating flow dynamics such as blood velocity, which typically increases in segments of stenosis. Although the combination of B-mode and Doppler ultrasonography improved the ability to localize the source of the reflected signal when it was involved with complicated blood velocity patterns (vasospasm, atherosclerosis), the signal was still quit difficult to interpret. lI'IOl'e recently, through the use of fast Fourier transformations, the complex signal was separated into a number of single-frequency components, which made it easier to interpret. These technologies were later integrated,

Answer 265

**A. B-mocle ultrasonography ** B. Doppler ultrasonography C. Both D. None of the above ## Footnote Brightness modulation ultrasonography (B mode), based on reflection of sound waves off tissue interfaces, is better used to view anatomic detail and can be used to measure blood vessel diameter and evaluate plaques. It typically shows the carotid system as a pulsatile luminal structure, with a thin echogenic line representing the intimal surface. The basic principle underlying this mode of imaging is the variable impedance that different body tissues naturally possess. Doppler shift ultrasonography is based on the reflection of sound waves off moving targets such as red blood cells. It is better for evaluating flow dynamics such as blood velocity, which typically increases in segments of stenosis. Although the combination of B-mode and Doppler ultrasonography improved the ability to localize the source of the reflected signal when it was involved with complicated blood velocity patterns (vasospasm, atherosclerosis), the signal was still quit difficult to interpret. lI'IOl'e recently, through the use of fast Fourier transformations, the complex signal was separated into a number of single-frequency components, which made it easier to interpret. These technologies were later integrated,

Answer 266

**A. B-mocle ultrasonography** B. Doppler ultrasonography C. Both D. None of the above ## Footnote Brightness modulation ultrasonography (B mode), based on reflection of sound waves off tissue interfaces, is better used to view anatomic detail and can be used to measure blood vessel diameter and evaluate plaques. It typically shows the carotid system as a pulsatile luminal structure, with a thin echogenic line representing the intimal surface. The basic principle underlying this mode of imaging is the variable impedance that different body tissues naturally possess. Doppler shift ultrasonography is based on the reflection of sound waves off moving targets such as red blood cells. It is better for evaluating flow dynamics such as blood velocity, which typically increases in segments of stenosis. Although the combination of B-mode and Doppler ultrasonography improved the ability to localize the source of the reflected signal when it was involved with complicated blood velocity patterns (vasospasm, atherosclerosis), the signal was still quit difficult to interpret. lI'IOl'e recently, through the use of fast Fourier transformations, the complex signal was separated into a number of single-frequency components, which made it easier to interpret. These technologies were later integrated,

Answer 267

A. B-mocle ultrasonography B. Doppler ultrasonography C. Both **D. None of the above** ## Footnote Brightness modulation ultrasonography (B mode), based on reflection of sound waves off tissue interfaces, is better used to view anatomic detail and can be used to measure blood vessel diameter and evaluate plaques. It typically shows the carotid system as a pulsatile luminal structure, with a thin echogenic line representing the intimal surface. The basic principle underlying this mode of imaging is the variable impedance that different body tissues naturally possess. Doppler shift ultrasonography is based on the reflection of sound waves off moving targets such as red blood cells. It is better for evaluating flow dynamics such as blood velocity, which typically increases in segments of stenosis. Although the combination of B-mode and Doppler ultrasonography improved the ability to localize the source of the reflected signal when it was involved with complicated blood velocity patterns (vasospasm, atherosclerosis), the signal was still quit difficult to interpret. lI'IOl'e recently, through the use of fast Fourier transformations, the complex signal was separated into a number of single-frequency components, which made it easier to interpret. These technologies were later integrated,

Answer 268

**A. Androgen receptor gene ** B. Dystrophin gene c. Superoxide dismutase gene D. TGF-~ receptor gene E. Mitochondrial complex 1 gene ## Footnote Spinobulbar muscular atrophy (SBMA), or Kennedy's disease, is a trinucleotide repeat disorder (CAG) that involves mutations of the androgen receptor gene, which is located on the X chromosome. It is an X-linked recessive disorder that typically affects adult males in the third decade of life and results in lower motor neuron degeneration only. Symptoms are similar to ALS and include dysarthria, dysphagia, limb wealmess, hyporeflexia , and tongue fasciculations. 5MBA progresses much more slowly than ALS, and patients may survive for extended periods after initial symptom onset (Merritt, pp. 709-710).

Answer 269

A. Vitamin B" decreases effective dose of levodopa B. MAO inhibitors can exaggerate the central dopamine effects by decreasing metabolism of dopamine C. Can cause orthostatic hypotension D. Carbidopa can increase the effectiveness of levodopa by inhibiting a peripheral decarboxylase inhibitor **E. Antipsychotics increase the efficacy oflevodopa ** ## Footnote Antipsychotics decrease the efficacy of levodopa by inhibiting D2 receptors. Dose-related, reversible side effects include nausea , vomiting, orthostatic hypotension, dyskinesias, restlessness, amdety, athetosis, insomnia, hallucinations, mania , nightmares, and dystonia (Merritt, pp. 689- 691).

Answer 270

A. Central seventh cranial nerve **B. Lower seventh cranial nerve ** C. Olfactory nerve D. Mandibular division of the trigeminal nerve E. Trochlear nerve ## Footnote The Ramsay Hunt syndrome is associated with herpetic infections of the geniculate ganglion. Herpetic eruptions may appear in the pinna , EAC, and possibly on the tympanic membrane. It is most often associated with a lowe r seventh cranial nerve palsy, although there may also be decreased hearing, tinnitus, andlor vertigo from involvement of CN VIII (Greenberg, p. 381).

Answer 271

A. Nigrostriatal B. Tuberoinfundibular C. Mesocortical **D. Mesolimbic ** E. Tuberolimbic ## Footnote The positive symptoms of schizophrenia, such as hallucinations, are the direct result of dopamine overactivity in the mesolimbic pathway. Most an tipsychotics work by blocking the dopamine receptors in this pathway and often work well for the positive symptoms of schizophrenia. The nega tive symptoms (flat affect, decreased motivation) are the result of decreased dopamine in the mesocortical system and are often not improved with the commencement of antipsychotics (Kandel, p. 1203).

Answer 272

**A. 1,2, and 3 are correct ** B. 1 and3 are correct C. 2 and 4 are correct D. Only 4 is correct E. All of the above ## Footnote The masseter, temporalis, and medial pterygoid muscles are the prime elevators of the mandible , whereas th e buccinator muscle compresses the cheek (April, pp. 496, 504).

Answer 273

A. Evidence of posterior interhemispheric blood after head trauma **B. Empty delta sign of superior sagittal thrombosis associated with a cystic tumor ** C. Pineocytoma D. A hyperdense MCA sign E. A left posterior temporal infarct ## Footnote Note the empty delta sign, representing an occluded superior sagittal sinus. This abnormality may be associated with pregnancy, dehydration , infections, hypercoagulable states, and tumors (as in this case) (Merritt, pp. 269- 271).

Answer 274

A. Most patients are mildly hypernatremic B. HHNS is often accompanied by severe prerenal azotemia C. I-IHNS is associated with an anion gap D. J\'Iost patients are hypokalemic **E. Insulin is always administered in the initial management period** ## Footnote Insulin mayor may not be used initially in patients with HHNS. Serum glucose levels may drop precipitously with fluid replacement alone. Insulin is required for patients who are acidotic , hyperkalemic, or in renal failure. If insulin is used, it must be administered in a low-dose regimen as a continuous infusion. To avoid overcorrection, glucose levels must be monitored frequently and the insulin drip stopped once glucose levels fall below 300 mg/dL or so. At this point 5% dextrose should be added to the infusion. Treatment of I-IH1\TS focuses primarily 011 replacing fluid losses, which may be up to 9 to 12 L in some cases, as well as correcting the

Answer 275

A. Methotrexate B. Vincristine **C. Bleomycin ** D. None of the abovE ## Footnote Methotrexate may cause leukoencephalopathy, myelosuppression, nephrotoxicity, and mucositis; if administered intrathecally, it can cause arachnoiditis. Bleomycin is associated with Raynaud's phenomenon, myelosuppression, and pulmonary fibrosis, while vincristine can calise a peripheralnel1l'opathy (Kay and Laws, pp. 381-383).

Answer 276

**A. Methotrexate ** B. Vincristine C. Bleomycin D. None of the abovE ## Footnote Methotrexate may cause leukoencephalopathy, myelosuppression, nephrotoxicity, and mucositis; if administered intrathecally, it can cause arachnoiditis. Bleomycin is associated with Raynaud's phenomenon, myelosuppression, and pulmonary fibrosis, while vincristine can calise a peripheralnel1l'opathy (Kay and Laws, pp. 381-383).

Multidisciplinary Self Assessment Examination Flashcards

(301 cards)