Neuroanatomy

Question 1

The medial posterior choroidal artery originates from which segment of the posterior cerebral artery?
A. P1
B. P2
C. P3
D. P4

Answer 1

A. P1
B. P2
C. P3
D. P4

Ascending deep to the rest of the PCA, the medial posterior choroidal artery supplies the tegmentum, midbrain, posterior thalamus and pineal gland as the cisternal segment. It then penetrates the velum interpositum, running in the roof of the third ventricle supplying the choroid plexus. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, vascular anatomy section.

Question 2

While performing an anterior temporal lobectomy, your medial resection ends at the ambient cistern. What cranial nerve passes through this space?
A. Trigeminal
B. Oculomotor
C. Trochlear
D. Optic

Answer 2

A. Trigeminal
B. Oculomotor
C. Trochlear
D. Optic

Structures passing through the ambient cistern include the posterior cerebral artery, the supracerebellar artery, the basal veins of Rosenthal and the trochlear nerve (CN IV). Further Reading: Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, chapter 4, trochlear nerve.

Question 3

The vidian artery originates from which segment of the internal carotid artery?
A. Cavernous
B. Lacerum
C. Ophthalmic
D. Petrous

Answer 3

A. Cavernous
B. Lacerum
C. Ophthalmic
D. Petrous

The vidian artery originates from the C2 segment of the ICA, the petrous segment. It passes through the vidian canal and can anastamose with a branch of the internal maxillary artery forming an ICA/ECA anastamosis site. The other branch from the C2 (petrous segment) is the caroticotympanic artery. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, vascular anatomy section.

Question 4

While operating on an anterior convexity meningioma, you attempt to obtain negative margins around the tumor. What structure do you need to disconnect the falx from to ensure a clean inferior margin
A. Crista galli
B. Anterior clinoid
C. Orbital roof
D. Sphenoid ridge

Answer 4

A. Crista galli
B. Anterior clinoid
C. Orbital roof
D. Sphenoid ridge

The crista galli is a structure arising from the surface of the ethmoid bone, serving as the point of attachment for the falx. It is a midline structure and projects into the anterior cranial fossa. Further Reading: Wanibuchi, Friedman, Fukushima. Photo Atlas of Skull Base Dissection, 2009, bifrontal transbasal approach.

Question 5

Brodmann area 17 is supplied by which artery?
A. Superior cerebellar artery
B. Callosal marginal artery
C. Calcarine artery
D. Splenial artery

Answer 5

A. Superior cerebellar artery
B. Callosal marginal artery
C. Calcarine artery
D. Splenial artery

Brodmann area 17 is the primary visual cortex (V1), also known as the calcarine cortex, and it is the primary input of signals coming from the retina. This cortical region lies inferior to the calcarine sulcus in the medial border of the occipital lobe. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, vascular anatomy section.

Question 6

Brodmann area 44 corresponds to which cortical region?
A. Precentral gyrus
B. Inferior frontal gyrus
C. Gyrus rectus
D. Middle frontal gyrus

Answer 6

A. Precentral gyrus
B. Inferior frontal gyrus
C. Gyrus rectus
D. Middle frontal gyrus

Brodmann area 44 corresponds to the inferior frontal gyrus, or Broca’s area. It is made of three structures, from anterior to posterior, the pars orbitalis, the pars triangularis and the pars opercularis. Broca’s area is thought to be formed mainly by the pars triangularis and the pars opercularis. Further Reading: Greenberg. Handbook of Neurosurgery. 8th edition, 2016, gross anatomy cranial and spine.

Question 7

The lentiform nucleus is comprised of which structures?
A. Caudate and putamen
B. Putamen and globus pallidus
C. Caudate and globus pallidus
D. Primary motor cortex and putamen

Answer 7

A. Caudate and putamen
B. Putamen and globus pallidus
C. Caudate and globus pallidus
D. Primary motor cortex and putamen

The lentiform nucleus is the combination of the putamen and globus pallidus. Lentiform nucleus comes from lenticular, meaning biconvex, similar to a lens. These structures appear lens-like, giving them this name. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition. 2016, gross anatomy cranial and spine.

Question 8

The claustrum separates which two structures?
A. Putamen and external capsule
B. Extreme capsule and insular cortex
C. Globus pallidus and internal capsule
D. External capsule and extreme capsule

Answer 8

A. Putamen and external capsule
B. Extreme capsule and insular cortex
C. Globus pallidus and internal capsule
D. External capsule and extreme capsule

he claustrum is a thin sheet of neurons separating the external capsule from the extreme capsule. It receives input from almost all regions of cortex and projects back to almost all regions of cortex. While exact function is not fully understood, it is currently thought to play a role in communication between cerebral hemispheres, and may play a role in attention. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, gross anatomy cranial and spine.

Question 9

While assessing a patient after a stroke, your exam identifies a pure conductive aphasia. Which structure has been damaged?
A. Arcuate fasciculus
B. Broca’s area
C. Wernicke’s area
D. Primary motor cortex

Answer 9

A. Arcuate fasciculus
B. Broca’s area
C. Wernicke’s area
D. Primary motor cortex

The arcuate fasciculus is a set of association fibers connecting the superior temporal gyrus/ angular gyrus (Wernicke’s region) to the inferior frontal gyrus (Broca’s area). Lesions disrupting these fibers lead to a conductive aphasia, whereby patients have difficulty repeating phrases, but productive and receptive language remains intact. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, gross anatomy cranial and spine.

Question 10

While clipping a posterior communicating artery aneurysm, the clip is inadvertently placed across an artery in the region. What postoperative deficit would not be expected after ligation of this artery?
A. Contralateral hemiparesis
B. Contralateral hemisensory loss
C. Contralateral hemianopia
D. Ipsilateral monocular blindness

Answer 10

A. Contralateral hemiparesis
B. Contralateral hemisensory loss
C. Contralateral hemianopia
D. Ipsilateral monocular blindness

The anterior choroidal artery arises from the internal carotid in the communicating segment (C7). It arises approximately 3 mm distal to the posterior communicating artery and 3 mm proximal from the ICA terminus. It has a characteristic superior bend as it crosses the tentorial edge. Anterior choroidal artery infarctions lead to a characteristic syndrome including contralateral hemiparesis, contralateral hemianesthesia and contralateral hemianiopia. Since the lesion is posterior to the optic chiasm, monocular blindness is not a part of the anterior choroidal artery syndrome. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition,. 2016, vascular anatomy section

Question 11

During exposure of an anterior communicating artery aneurysm, you decide to drain CSF directly from the third ventricle. In order to do this, you perforate a structure just posterior to the optic chiasm. This structure is formed on which day of embryologic development?
A. Day 22
B. Day 24
C. Day 26
D. Day 28

Answer 11

A. Day 22
B. Day 24
C. Day 26
D. Day 28

The lamina terminalis lies just posterior to the optic chiasm and may be perforated during exposure to drain CSF from the third ventricle and relax the brain. The lamina terminalis is formed after closure of the anterior neuropore on day 24 of development. The posterior neuropore closes on day 26, and forms the neural elements of the lumbar spine. Further Reading: Torres-Corzo, Rangel-Castilla, Nakaji. Neuroendoscopic Surgery, 2016, lamina terminalis fenestration.

Question 12

Which of the following is the correct association of a thalamic nucleus and its corresponding cortical projections?
A. Pulvinar–Cingulate gyrus
B. Anterior nuclei–Orbital frontal cortex and
frontal eye fields
C. Mediodorsal nuclei–Primary and secondary
visual cortices
D. Ventral posterolateral nuclei–Somatosensory
cortex

Answer 12

A. Pulvinar–Cingulate gyrus
B. Anterior nuclei–Orbital frontal cortex and frontal eye fields
C. Mediodorsal nuclei–Primary and secondary
visual cortices
D. Ventral posterolateral nuclei–Somatosensory cortex

The thalamus is comprised of multiple relay nuclei and their afferent/efferent projections are often tested on the written boards. The anterior nuclei receive input from the mammillothalamic tract and fornix and project largely to the cingulate cortex. The mediodorsal nuclei receive input from the amygdala, substantia nigra pars reticulata, hippocampus, hypothalamus and entire prefrontal cortex. They project to the orbital frontal cortex and frontal eye fields The VPL nuclei are the primary sensory relay station, they receive input from the medial lemniscus and both spinothalamic tracts (anterior and lateral). The VPL nuclei project to the somatosensory cortex. The pulvinar receives input from the superior colliculus and occipital striate cortex, sending projections to the primary and secondary visual cortices. Further Reading: Moore and Psaaros. Definitive neurologic surgery board review, 2005, page 39. Greenstein B, Greenstein A, Color Atlas of Neuroscience, 2000, thalamic nuclei section

Question 13

Which hippocampal region is most resistant to hypoxia?
A. CA1
B. CA2
C. CA3
D. CA4

Answer 13

A. CA1
B. CA2
C. CA3
D. CA4

The hippocampus is made of 4 regions. CA1, also known as Sommer’s sector, is extremely sensitive to hypoxia, while CA3 is located at the genu of the hippocampal formation and is relatively resistant to hypoxia. Further Reading: Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, the hippocampus.

Question 14

The main artery feeding the pachymeninges enters the skull through which foramen?
A. Foramen spinosum
B. Foramen lacerum
C. Foramen ovale
D. Foramen rotundum

Answer 14

A. Foramen spinosum
B. Foramen lacerum
C. Foramen ovale
D. Foramen rotundum

The primary artery feeding the pachymeninges is the middle meningial artery, and it enters the skull through the foramen spinosum. Further Reading: Moore and Psaaros. Definitive Neurologic Surgery Board Review, 2005, page 54. Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, brain vascularization, arterial supply

Question 15

In the roof of the third ventricle, where are the fornices in relation to the internal cerebral veins?
A. Medial
B. Superior
C. Lateral
D. Inferior

Answer 15

A. Medial
B. Superior
C. Lateral
D. Inferior

In the roof of the third ventricle, the body of the fornix resides superior to the paired internal cerebral veins. Further Reading: Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, venous drainage of the brain.

Question 16

Through what structure does the hypothalamus receive projections from the hippocampus?
A. Medial forebrain bundle
B. Fornix
C. Stria terminalis
D. Inferior longitudinal fasciculus

Answer 16

A. Medial forebrain bundle
B. Fornix
C. Stria terminalis
D. Inferior longitudinal fasciculus

Part of the Papez circuit, the hypothalamus receives input from the hippocampus through the fornix, which projects to the hypothalamic septal, dorsal and lateral preoptic regions through the precommissural fibers, and to the mammillary bodies through the postcommissural fibers. Information is then sent to the thalamus through the mammillothalamic tract. Further Reading: Moore and Psaaros. Definitive Neurologic Surgery Board Review, 2005, pages 44, 45. Greenstein B, Greenstein A. Color

Question 17

What is the largest input to the amygdala?
A. Locus ceruleus
B. Ventral tegmentum
C. Nucleus basalis of Meynert
D. Insular cortex

Answer 17

A. Locus ceruleus
B. Ventral tegmentum
C. Nucleus basalis of Meynert
D. Insular cortex

The amygdala is part of the limbic system and receives input from all structures mentioned above. By far, the largest input to the amygdala is through the insular cortex. Further Reading: Moore and Psaaros. Definitive Neurologic Surgery Board Review, 2005, page 48. Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, functions of the amygdaloid complex.

Question 18

Primary input to Brodmann areas 41 and 42 come from which region?
A. Medial geniculate body
B. Lateral geniculate body
C. Inferior colliculus
D. Superior colliculus

Answer 18

A. Medial geniculate body
B. Lateral geniculate body
C. Inferior colliculus
D. Superior colliculus

Brodmann areas 41 and 42 correspond to Heschel’s gyrus, or the primary auditory cortex located in the superior temporal gyrus. The primary input is the medial geniculate body. The lateral geniculate body and superior colliculus are involved in visual pathways, while the inferior colliculus provides projections to the medial geniculate body via the brachium of the inferior colliculus. Further Reading: Moore and Psaaros. Definitive Neurologic Surgery Board Review, 2005, page 28. Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, the special senses: auditory cortical areas and descending auditory pathways.

Question 19

You have been following a patient with epilepsy. Her seizure semiology consists of olfactory hallucinations followed by behavioral arrest, lip smacking and left upper extremity shaking. You offer surgical resection for attempted cure. What deficit is possible in this case if resection is carried too far posterior?
A. Right hemiplegia
B. Left hemiplegia
C. Left superior quadrantanopsia
D. Left inferior quadrantanopsia

Answer 19

A. Right hemiplegia
B. Left hemiplegia
C. Left superior quadrantanopsia
D. Left inferior quadrantanopsia

The seizure semiology presented in this case is classic for temporal lobe epilepsy, often caused by mesial temporal sclerosis. The symptoms from this patient localize to the right temporal lobe. This condition can be treated by selective amygdalohippocampectomy, or even complete temporal lobectomy. On the left side, resection of cortex should not exceed 4 to 5 cm to avoid harming language function presumed to be on the left side near the angular gyrus. On the right side, resection can often be safely carried 6 to 7 cm posterior given that language function is not presumed to be located on the right side. Care must be taken at the posterior-superior aspect of the resection in this region, as aggressive resection can involve the optic radiations (Meyer’s loop), causing the classic “pie in the sky” visual field cut, a contralateral superior quadrant anopsia. Further Reading: Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, the visual fields and pathways

Question 20

**

A 60-year-old man has bradykinesia, rigidity and impaired balance. You are performing a DBS electrode placement to the most commonly targeted nuclei that improve rigidity in this disorder. During test stimulation of the electrode, the patient develops ipsilateral eye deviation. Which direction should you move the electrode?
A. Lateral
B. Medial
C. Superior
D. Inferior

Answer 20

A. Lateral
B. Medial
C. Superior
D. Inferior

The patient has Parkinsonism, and you are performing bilateral STN deep brain stimulation. If ipsilateral eye deviation is noticed during test stimulation, your electrode is too medial and needs to be moved lateral. Efferent fibers ultimately forming the IIIrd nerve pass just medial to the STN and can be stimulated causing eye deviation if the electrode is too medial. Further Reading: Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, oculomotor nuclei and nerves.

Question 21

You are performing bilateral STN DBS for a patient with advanced Parkinsonism. During test stimulation, the patient develops contralateral facial pulling and contralateral arm twitching. Which direction should you move the electrode?
A. Anteromedial
B. Posteromedial
C. Anterolateral
D. Posterolateral

Answer 21

A. Anteromedial
B. Posteromedial
C. Anterolateral
D. Posterolateral

Descending corticospinal motor neuron tracts from the internal capsule travel anterolateral to STN. If contralateral facial pulling or muscle twitching is noted during test stimulation, the electrode is too far in the anterior or lateral position and should be moved posteromedially. Further Reading: Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, descending motor tracts and cranial nerve nuclei.

Question 22

You are performing DBS electrode placement for dystonia. While targeting the most common nuclei for this disorder, the patient develops contralateral muscle contractions, which direction do you need to move the electrode?
A. Lateral
B. Medial
C. Anterior
D. Posterior

Answer 22

A. Lateral
B. Medial
C. Anterior
D. Posterior

The most commonly targeted nucleus for patients with dystonia is GPI. If the DBS electrode is too medial, stimulation current can spread to the internal capsule, which is medial to the GPI nucleus. The electrode should be moved laterally. Further Reading: Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, cerebral hemispheres: internal structures.

Question 23

During a DBS lead placement for dystonia, your patient develops phosphenes in her visual field during test stimulation, which direction should you move the electrode
A. Inferior
B. Superior
C. Medial
D. Lateral

Answer 23

A. Inferior
B. Superior
C. Medial
D. Lateral

If a patient develops phosphenes in their visual field (flashing lights), it indicates that the electrode is too deep. Optic pathways run inferior to the GPI nuclei, and the electrode should be moved superiorly. Further Reading: Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, cerebral hemispheres: internal structures.

Question 24

You are placing DBS electrodes in a 45-year-old man who has been diagnosed with essential tremor. While targeting the most common nuclei for this disorder, your patient develops muscle contractions during test stimulation. Which direction should you move the electrode?
A. Inferior
B. Superior
C. Medial
D. Lateral

Answer 24

A. Inferior
B. Superior
C. Medial
D. Lateral

For essential tremor, DBS electrode placement into bilateral VIM thalamus has shown excellent results. The internal capsule is lateral to the thalamus, and if your patient develops muscle contractions, you should move the electrode medially. Further Reading: Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, origin of the pyramidal tract.

Question 25

While placing DBS electrodes for essential tremor into VIM thalamus, the patient develops persistent paresthesias during test stimulation. Which direction should you move the electrode
A. Anterior
B. Posterior
C. Medial
D. Lateral

Answer 25

A. Anterior
B. Posterior
C. Medial
D. Lateral

VIM thalamus is just anterior to the VPL nucleus of the thalamus, the main sensory relay nucleus of the thalamus. If the electrode is placed correctly into VIM, patients can develop transient paresthesias during test stimulation, but these symptoms often resolve quite quickly. If the patient develops persistent paresthesias, current is likely spreading into VPL thalamus, and the electrode should be moved anteriorly. Further Reading: Israel, Burchiel, Microelectrode Recording in Movement Disorder Surgery, 2004, target selection using microelectrode recording

Question 26

You are exposing a right sided ICA terminus aneurysm for surgical clipping. You decide to dissect along the MCA (M1 segment) to reach the ICA terminus and the aneurysm. Which area of the M1 segment of the MCA is considered safe?
A. Posterosuperior
B. Posteroinferior
C. Anterosuperior
D. Anteroinferior

Answer 26

A. Posterosuperior
B. Posteroinferior
C. Anterosuperior
D. Anteroinferior

Utilizing the MCA M1 segment to reach the ICA terminus is one technique to expose an ICA terminus aneurysm. The main concern dissecting along the M1 segment of the MCA is preservation of the lateral lenticulostriate perforating arteries, which are located on the posterosuperior aspect of the M1 segment. The safe zone of dissection is on the anteroinferior surface of the vessel. Further Reading: Spetzler, Kalani, Nakaji. Neurovascular Surgery, 2nd edition, 2015, surgical therapies for saccular aneurysms of the internal carotid artery.

Question 27

This structure connects the temporal and orbital cortical regions. Medially it is bordered by the anterior perforated substance. Laterally it is bordered by the insular cortex.
A. Medial forebrain bundle
B. Limen insulae
C. Inferior longitudinal fasciculus
D. Diagonal band of Broca

Answer 27

A. Medial forebrain bundle
B. Limen insulae
C. Inferior longitudinal fasciculus
D. Diagonal band of Broca

The limen insula is a structure that connects the temporal and orbital cortical regions. It often marks the MCA bifurcation, and laterally is continuous with the insular cortex. Medially it is bordered by the anterior perforated substance. Further Reading: Starr, Barbaro, Larson, Neurosurgical Operative Atlas: Functional Neurosurgery, 2nd edition, 2009, surgical anatomy of the temporal lobe.

Question 28

You are performing an anterior interhemispheric approach to the third ventricle for a presumed teratoma. In order to expose the corpus callosum for division, you must retract the cortex. What is the gyrus located immediately superior to the corpus callosum
A. Cingulate gyrus
B. Paracentral lobule
C. Supramarginal gyrus
D. Precentral gyrus

Answer 28

A. Cingulate gyrus
B. Paracentral lobule
C. Supramarginal gyrus
D. Precentral gyrus

The cingulate gyrus is located immediately superior to the corpus callosum, and must be gently retracted to expose the corpus callosum for division. Care must be taken to avoid damaging the pericallosal arteries, which are also running immediately over the corpus callosum Further Reading: Sekhar, Fessler, Atlas of Neurosurgical Techniques: Brain, Vol. 2, 2016, surgical approaches to lesions located in the lateral, third, and fourth ventricles

Question 29

Which vein does not drain directly into the great cerebral vein of Galen?
A. Precentral cerebellar vein
B. Basal vein of Rosenthal
C. Internal cerebral vein
D. Thalamostriate vein

Answer 29

A. Precentral cerebellar vein
B. Basal vein of Rosenthal
C. Internal cerebral vein
D. Thalamostriate vein

The vein of Galen may have numerous supplying veins, but most often it receives the paired internal cerebral veins, the paired basal veins of Rosenthal and the precentral cerebellar vein. The thalamostriate vein of the lateral ventricle drains into the internal cerebral vein at the venous angle near the foramen of Monro, but this vein does not directly drain into the vein of Galen. Further Reading: Spetzler, Kalani, Nakaji. Neurovascular Surgery, 2nd edition, 2015, microsurgical treatment of vein of Galen malformations

Question 30

You are performing an ETV on a pediatric patient for congenital acqueductal stenosis. You are looking at the floor of the third ventricle and you have identified the mammillary bodies. Which direction in relation to the mammillary bodies is the safe zone for puncture?
A. Anterior
B. Lateral
C. Posterior
D. Medial

Answer 30

A. Anterior
B. Lateral
C. Posterior
D. Medial

During an endoscopic third ventriculostomy, one of the easiest structures to identify are the paired mammillary bodies. Just anterior to the mammillary bodies is the safe zone for puncture. Care must be taken to not injure the basilar artery or posterior cerebellar arteries, which are just deep and slightly posterior to the puncture location Further Reading: Torres-Corzo, Rangel-Castilla, Nakaji. Neuroendoscopic Surgery, 2016, lateral and third ventricle anatomy

Question 31

In the anterior floor of the third ventricle, what structure is located just above the supraoptic recess?
A. Anterior commissure
B. Lamina terminalis
C. Optic chiasm
D. Mammillary bodies

Answer 31

A. Anterior commissure
B. Lamina terminalis
C. Optic chiasm
D. Mammillary bodies

In the anterior floor of the third ventricle, the lamina terminalis is located superior to the supraoptic recess. It is formed during closure of the anterior neuropore on embryological day 24. Division of the lamina terminalis allows access to the third ventricle for drainage of CSF and brain relaxation if required during anterior fossa aneurysm surgery. Further Reading: Torres-Corzo, Rangel-Castilla, Nakaji. Neuroendoscopic, Surgery, 2016, lateral and third ventricle anatomy.

Question 32

Descending laterally across the posterior skull, which suture marks the border between the occipital and parietal bones?
A. Squamosal
B. Coronal
C. Lambdoid
D. Sphenosquamosal

Answer 32

A. Squamosal
B. Coronal
C. Lambdoid
D. Sphenosquamosal

The lambdoid suture connects the occipital and parietal bones while descending laterally across the posterior skull. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, gross anatomy, cranial and spine.

Question 33

Which sutures connect to form the bregma?
A. Sagittal-lambdoid
B. Parietomastoid-occipitomastoid
C. Squamosal-parietomastoid
D. Coronal-sagittal

Answer 33

A. Sagittal-lambdoid
B. Parietomastoid-occipitomastoid
C. Squamosal-parietomastoid
D. Coronal-sagittal

The bregma is a midline skull structure that is the location where the coronal and sagittal sutures conjoin. It is the location of the anterior fontanelle, which closes in most pediatric patients around 18 months of age. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, gross anatomy, cranial and spine.

Question 34

Which structure is not part of the deep cerebellar nuclei?
A. Globose
B. Fastigial
C. Emboliform
D. Vestibular

Answer 34

A. Globose
B. Fastigial
C. Emboliform
D. Vestibular

The deep cerebellar nuclei are the dentate, emboliform, globose and fastigial, going from lateral to medial. A mnemonic to remember is “Don’t Eat Greasy Foods.” Since the deep cerebellar nuclei control all output from the cerebellum, damage to these structures can mimic a complete cerebellar resection and are considered by some to be “eloquent cortex.” Further Reading: Psarros. The Definitive Neurosurgical Board Review. Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, cerebellum.

Question 35

Which structure forms the superolateral border of the 4th ventricle?
A. Brachium conjunctivum
B. Restiform body
C. Brachium pontis
D. Vermis

Answer 35

A. Brachium conjunctivum
B. Restiform body
C. Brachium pontis
D. Vermis

The 4th ventricle has lateral walls formed superiorly by the superior cerebellar peduncle (brachium conjunctivis), and lateral walls formed inferiorly by the inferior cerebellar peduncle (restiform body). The middle cerebellar peduncle (brachium pontis) does not form a lateral wall of the 4th ventricle. The roof of the 4th ventricle is formed by both the superior and inferior medullary velum, and the floor is formed by the brainstem. Further Reading: Psarros. The Definitive Neurosurgical Board Review. Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, cerebellum.

Question 36

Which structure forms the inferolateral border of the 4th ventricle?
A. Brachium conjunctivum
B. Restiform body
C. Brachium pontis
D. Vermis

Answer 36

A. Brachium conjunctivum
B. Restiform body
C. Brachium pontis
D. Vermis

The 4th ventricle has lateral walls formed superiorly by the superior cerebellar peduncle (brachium conjunctivis), and lateral walls formed inferiorly by the inferior cerebellar peduncle (restiform body). The middle cerebellar peduncle (brachium pontis) does not form a lateral wall of the 4th ventricle. The roof of the 4th ventricle is formed by both the superior and inferior medullary velum, and the floor is formed by the brainstem. Further Reading: Psarros. The Definitive Neurosurgical Board Review. Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, cerebellum

Question 37

Which cerebellar lobe forms what is considered to be the functional cerebellar division known as the vestibulocerebellum?
A. Anterior lobe
B. Posterior lobe
C. Vermis
D. Flocculonodular lobe

Answer 37

A. Anterior lobe
B. Posterior lobe
C. Vermis
D. Flocculonodular lobe

The cerebellum can be divided in to three functional segments, the vestibulocerebellum, the spinocerebellum and the cerebrocerebellum. The vestibulocerebellum is formed by the flocculonodular lobe and it receives projections from the vestibular nuclei, the superior colliculi and visual cortex. This system controls head and eye movements as well as postural and balance adjustments. Further Reading: Psarros. The Definitive Neurosurgical Board Review, page 37. Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, cerebellum.

Question 38

Which cerebellar region forms what is considered to be the functional cerebellar division known as the cerebrocerebellum?
A. Anterior lobe
B. Lateral hemisphere
C. Vermis
D. Flocculonodular lobe

Answer 38

A. Anterior lobe
B. Lateral hemisphere
C. Vermis
D. Flocculonodular lobe

The functional division of the cerebellum known as the cerebrocerebellum is comprised of the lateral hemispheres. It projects to the dentate nucleus of the deep cerebellar nuclei. Further connections include the VL nuclei of the thalamus and red nucleus, followed by motor cortex, and helps to provide feedback to motor cortex regarding accuracy of movement. Further Reading: Psarros. The Definitive Neurosurgical Board Review, page 37. Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, cerebellum

Question 39

Which cerebellar region forms what is considered to be the functional cerebellar division known as the spinocerebellum?
A. Anterior lobe
B. Lateral hemisphere
C. Vermis
D. Flocculonodular lobe

Answer 39

A. Anterior lobe
B. Lateral hemisphere
C. Vermis
D. Flocculonodular lobe

The functional division of the cerebellum known as the spinocerebellum is comprised mainly of the vermis. It projects to the fastigial nucleus of the deep cerebellar nuclei. It receives afferent connections from the spinocerebellar tract. Efferent connections from the fastigial nucleus project to the reticular formation and lateral vestibular nuclei, as well as the contralateral motor cortex via the VL thalamus. Further Reading: Psarros. The Definitive Neurosurgical Board Review, page 37. Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, cerebellum

Question 40

What is the primary output of the paramedian pontine reticular formation (PPRF)?
A. Trochlear nucleus
B. Abducens nucleus*
C. Oculomotor nucleus
D. Facial nucleus

Answer 40

A. Trochlear nucleus
B. Abducens nucleus
C. Oculomotor nucleus
D. Facial nucleus

The paramedian pontine reticular formation is also known as the lateral gaze center, and it is located near the abducens nucleus. It receives input from the superior colliculus to coordinate vertical eye movements, and from the frontal eye fields via the frontopontine fibers to coordinate lateral gaze. Contralateral eye movement in a conjugate fashion is mediated by crossing fibers from the medial longitudinal fasciculus. Further Reading: Psarros. The Definitive Neurosurgical Board Review, page 33. Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, brainstem

Question 41

You are evaluating a patient with double vision. When you are testing external ocular movements, the right eye fails to adduct when you attempt to make the patient track your finger to the patient’s left. What structure is likely damaged?
A. Right abducens nerve
B. Medial longitudinal fasciculus
C. Left abducens nerve
D. Medial lemniscus

Answer 41

A. Right abducens nerve
B. Medial longitudinal fasciculus
C. Left abducens nerve
D. Medial lemniscus

In this scenario, the patient is not able to adduct the right eye when attempting to look left, while the left eye is able to abduct. This likely represents a lesion of the medial longitudinal fasciculus. Further Reading: Psarros. The Definitive Neurosurgical Board Review, page 32. Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, vestibular system.

Question 42

After resecting a 4th ventricular subependymoma, you are viewing the floor of the 4th ventricle. You notice bilateral raised circular structures. What is the most likely structure that you notice?
A. Trochlear nuclei
B. Facial colliculus
C. Stria medullaris
D. Middle cerebellar peduncle

Answer 42

A. Trochlear nuclei
B. Facial colliculus
C. Stria medullaris
D. Middle cerebellar peduncle

The paired facial colliculi form noticeable structures on surface of the floor of the 4th ventricle. They are located above the bilateral stria medullari. Care should be taken to not violate the floor of the 4th ventricle. Further Reading: Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, facial nerve

Question 43

On the floor of the 4th ventricle, the vagal trigone is located where in relation to the hypoglossal trigone?
A. Medial
B. Lateral
C. Superior
D. Inferior

Answer 43

A. Medial
B. Lateral
C. Superior
D. Inferior

There are several observable structures on the surface of the floor of the 4th ventricle. The paired facial colliculi are prominences that can be seen above the laterally projecting fibers of the stria medullari. Below the stria, the hypoglossal trigone is closest to midline, with the vagal trigone located lateral to the hypoglossal trigone. Further Reading: Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, vagus nerve

Question 44

Myelinated neurons from the nucleus gracilis and nucleus cuneatus decussate in the medulla to form the medial lemniscus. What are the decussating connections called?
A. Medial longitudinal fasciculus
B. Internal arcuate fibers
C. Pyramids
D. Mossy fibers

Answer 44

A. Medial longitudinal fasciculus
B. Internal arcuate fibers
C. Pyramids
D. Mossy fibers

The nuclei gracilis and cuneatus receive sensory input from the dorsal columns of the spinal cord. In the medulla they decussate and form the medial lemniscus. The decussating fibers cross the midline as internal arcuate fibers. Further Reading: Psarros. The Definitive Neurologic Surgery Board Review, page 30. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatomy.

Question 45

What is the only paired circumventricular organ?
A. Area prostrema
B. Subforniceal organ
C. Vascular organ of the lamina terminalis
D. Subcommissural organ

Answer 45

A. Area prostrema
B. Subforniceal organ
C. Vascular organ of the lamina terminalis
D. Subcommissural organ

The circumventricular organs are regions of the brain located at the boundaries of the ventricular system and they are regions with an incomplete blood brain barrier. This allows these regions to sense peptide levels within the brain without requiring active transport mechanisms. There circumventricular organs include the median eminence, posterior pituitary, subcommissural organ, subforniceal organ, area prostrema, choroid plexus, vascular organ of the lamina terminalis and pineal gland. The only paired circumventricular organ is the area prostrema. Further Reading: Psarros. The definitive Neurologic Surgery Board Review, page 30. Yaşargil, Adamson, Cravens, Johnson, Reeves, Teddy, Valavanis, Wichmann, Wild, Young. Microneurosurgery IV A, 1994, neurophysiology.

Question 46

Within the cerebral peduncles, the descending corticospinal tract fibers controlling sacral function are located where?
A. Medially
B. Anteriorly
C. Laterally
D. Posteriorly

Answer 46

A. Medially
B. Anteriorly
C. Laterally
D. Posteriorly

The cerebral peduncles contain descending corticospinal tracts organized in a somatotopic organization with the sacral fibers occupying the most lateral aspect of the corticospinal tracts, and fibers controlling the head/arms are the most medial. Further Reading: Psarros. The Definitive Neurologic Surgery Board Review, page 34. Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, brainstem.

Question 47

The oculomotor nucleus is located at which horizontal level within the brainstem?
A. Cerebral peduncles
B. Superior colliculi
C. Inferior colliculi
D. Pons

Answer 47

A. Cerebral peduncles
B. Superior colliculi
C. Inferior colliculi
D. Pons

The nucleus of the IIIrd nerve, the occulomotor nucleus, is located roughly at the same horizontal level as the superior colliculi. Further Reading: Psarros. The Definitive Neurologic Surgery Board Review, page 34. Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, brainstem.

Question 48

Which nucleus is the center of control for the direct and consensual pupillary light reflex?
A. Interstitial nucleus of Cajal
B. Oculomotor
C. Pretectal
D. Trochlear

Answer 48

A. Interstitial nucleus of Cajal
B. Oculomotor
C. Pretectal
D. Trochlear

The pretectal nucleus controls the direct and consensual pupillary light reflex Further Reading: Psarros. The Definitive Neurologic Surgery Board Review, page 34. Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, visual system.

Question 49

What is the only circumventricular organ to have an intact blood brain barrier?
A. Subcommissural organ
B. Subforniceal organ
C. Area prostrema
D. Pineal gland

Answer 49

A. Subcommissural organ
B. Subforniceal organ
C. Area prostrema
D. Pineal gland

The subcommissural organ is made of ependymal cells that secrete somatostatin. It is the only circumventricular organ with an intact blood brain barrier. Further Reading: Psarros. The Definitive Neurologic Surgery Board Review, page 34. Yaşargil, Adamson, Cravens, Johnson, Reeves, Teddy, Valavanis, Wichmann, Wild, Young. Microneurosurgery IV A, 1994, neurophysiology

Question 50

What structure is located lateral to the red nucleus within the midbrain?
A. IIIrd nerve fibers
B. Periacqueductal grey
C. Medial longitudinal fasciculus
D. Medial lemniscus

Answer 50

A. IIIrd nerve fibers
B. Periacqueductal grey
C. Medial longitudinal fasciculus
D. Medial lemniscus

The medial lemniscus appears as a curved structure projecting laterally from the red nucleus on a horizontal section through the midbrain. Further Reading: Psarros. The Definitive Neurologic Surgery Board Review, page 35. Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, brainstem.

Question 51

Which artery provides the majority of blood supply to the deep cerebellar nuclei?
A. Anterior inferior cerebellar artery
B. Posterior inferior cerebellar artery
C. Superior cerebellar artery
D. Posterior cerebral artery

Answer 51

A. Anterior inferior cerebellar artery
B. Posterior inferior cerebellar artery
C. Superior cerebellar artery
D. Posterior cerebral artery

The deep cerebellar nuclei are located very close to the superior cerebellar peduncle within the vicinity of the superior lateral wall of the 4th ventricle. The superior cerebellar artery provides blood supply to the superior surface of the cerebellum as well as to the superior cerebellar peduncle and the majority of the deep cerebellar nuclei. Further Reading: Psarros. The Definitive Neurologic Surgery Board Review, page 38. Spetzler, Kalani, Nakaji. Neurovascular Surgery, 2nd edition, 2015, cranial vascular anatomy of the posterior circulation

Question 52

Within the midbrain, the descending corticospinal tracts are arranged somatotopically. The tracts controlling function of the upper extremity are in which direction compared to tracts controlling the lower extremity?
A. Lateral
B. Posterior
C. Medial
D. Anterior

Answer 52

A. Lateral
B. Posterior
C. Medial
D. Anterior

At the level of the midbrain, the descending corticospinal tracts are located in the ventral region of the midbrain and are arranged in a somatotopic fashion. The tracts controlling the upper extremity are located medial to tracts controlling lower extremity function. Further Reading: Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, brainstem.

Question 53

At the level of the midbrain, fibers conveying sensory information from the upper extremity are in what position relative to the fibers conveying information from the lower extremity?
A. Medial
B. Lateral
C. Anterior
D. Posterior

Answer 53

A. Medial
B. Lateral
C. Anterior
D. Posterior

At the level of the medulla, after the internal arcuate fibers have crossed and formed the medial lemniscus, the fibers conveying information from the upper extremity are located dorsal and the fibers from the lower extremity are located ventrally. As these fibers ascend to the level of the midbrain, the medial lemniscus becomes a curve structure extending laterally from the red nucleus. In this region, the fibers from the upper extremity are the most medial, while the lower extremity fibers are located laterally. Further Reading: Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, brainstem

Question 54

Which of these structures pass through the tendinous ring of the orbit (annulus of Zinn)?
A. Frontal nerve
B. Trochlear nerve
C. Lacrimal nerve
D. Nasociliary nerve

Answer 54

A. Frontal nerve
B. Trochlear nerve
C. Lacrimal nerve
D. Nasociliary nerve

The annulus of Zinn is a structure located in the superior orbital fissure, dividing it into sections. There are multiple structures that pass through the annulus of Zinn, including the oculomotor nerve, the nasociliary nerve, the abducens nerve and roots of the ciliary ganglion. The frontal nerve, trochlear nerve and lacrimal nerve all pass outside of the annulus of Zinn. Further Reading: Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatomy.

Question 55

While exposing the posterior fossa via an extended retrosigmoid craniotomy for a brainstem tumor, you decide to divide the tentorium to increase your superior access. If you inadvertently injure a nerve while dividing the tentorium, what deficit is the patient likely to experience?
A. Lateral rectus palsy
B. Medial rectus palsy
C. Superior oblique palsy
D. Monocular visual loss

Answer 55

A. Lateral rectus palsy
B. Medial rectus palsy
C. Superior oblique palsy
D. Monocular visual loss

The IVth nerve (trochelar nerve), runs at the edge of the tentorial incisura in the ambient cistern and is at risk during complete division of the tentorium. Further Reading: Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, trochlear nerve.

Question 56

You are evaluating a patient for brain death and choose to perform a cold calorics test in the right ear. If the vestibular nuclei are intact, what eye movements do you expect to observe?
A. Nystagmus to the right
B. Nystagmus to the left
C. Superior nystagmus
D. Ocular bobbing

Answer 56

A. Nystagmus to the right
B. Nystagmus to the left
C. Superior nystagmus
D. Ocular bobbing

Cold calorics involve irrigating cold saline into the patient’s ear and observing the movements of the eyes. The mnemonic COWS (cold-opposite, warm-same) is useful to remember, but it must be noted that this mnemonic refers to the nystagmus portion of the eye movements. In this patient, you irrigate the right ear with cold saline, and you would expect a slow drift of the eyes to the right followed by a fast-jerk nystagmus back to the left. The cold saline decreases the temperature of the tympanic membrane and hyperpolarizes the vestibular cells, tricking the system into thinking the head is moving to the left. Further Reading: Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, vestibular system.

Question 57

The cochlea is arranged tonotopically. Where are high frequency sounds processed?
A. Base
B. Apex
C. Scala vestibuli
D. Scala tympani

Answer 57

A. Base
B. Apex
C. Scala vestibuli
D. Scala tympani

The cochlea is a coiled organ that process auditory input. It is arranged tonotopically with high frequency sounds processed at the base, and low-frequency sounds processed at the apex. Further Reading: Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, auditory system.

Question 58

What is the name of the structure that deflects the ciliary processes of the inner and outer hair cells within the cochlea?
A. Tectorial membrane
B. Basilar membrane
C. Scala vestibuli
D. Scala tympani

Answer 58

A. Tectorial membrane
B. Basilar membrane
C. Scala vestibuli
D. Scala tympani

As sound travels through the cochlea it causes movement of the basilar membrane, which in turn moves the organ of Corti at specific locations. This movement causes a shearing motion against the tectorial membrane, to which the ciliary processes of the hair cells are connected. This movement causes opening of these processes and depolarization of the hair cells Further Reading: Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, auditory system.

Question 59

As a part of the slow acting auditory system, the trapezoid body connects which two structures?
A. Ventral cochlear nucleus–inferior colliculus
B. Ventral cochlear nucleus–medial geniculate
body
C. Ventral cochlear nucleus–superior olive
D. Ventral cochlear nucleus–inferior olive

Answer 59

A. Ventral cochlear nucleus–inferior colliculus
B. Ventral cochlear nucleus–medial geniculate
body
C. Ventral cochlear nucleus–superior olive
D. Ventral cochlear nucleus–inferior olive

The trapezoid body conveys information from the cochlear nucleus to the superior olive. Fibers then travel to the inferior colliculus and subsequently the medial geniculate body. Further Reading: Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, auditory system

Question 60

You are watching a 100-m dash at a local track event. You are frightened by the sound of the starting gun and you jump. This response is mediated by the fast-acting auditory pathway. As a part of the fast-acting auditory pathway, the dorsal cochlear nucleus sends fibers to the inferior colliculus via what structure?
A. Medial lemniscus
B. Trapezoid body
C. Lateral lemniscus
D. Restiform body

Answer 60

A. Medial lemniscus
B. Trapezoid body
C. Lateral lemniscus
D. Restiform body

The lateral lemniscus connects the dorsal cochlear nucleus to the inferior colliculus via the lateral lemniscus. It is involved in the response to sudden loud noises. Further Reading: Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, auditory system.

Question 61

While evaluating a patient for brain death, you use a small amount of irrigation to the cornea to look for a blink. What brainstem structure mediates this reflex?
A. Spinal trigeminal nucleus
B. Oculomotor nucleus
C. Superior olive
D. Abducens nucleus

Answer 61

A. Spinal trigeminal nucleus
B. Oculomotor nucleus
C. Superior olive
D. Abducens nucleus

The corneal blink reflex pathway involves sensory information from the cornea passing through the trigeminal nerve to the spinal trigeminal nucleus and tract. Further connections include the bilateral facial nuclei which mediate eye closure. Further Reading: Rohkamm. Color Atlas of Neurology, 2007, normal and abnormal function of the nervous system.

Question 62

Which fibers travel around the abducens nucleus?
A. Spinal trigeminal tract
B. Facial nerve
C. Medial longitudinal fasciculus
D. Internal arcuate fibers

Answer 62

A. Spinal trigeminal tract
B. Facial nerve
C. Medial longitudinal fasciculus
D. Internal arcuate fibers

Fibers traveling from the facial nucleus travel around the abducens nucleus in the brainstem. Further Reading: Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, facial nerve.

Question 63

Which hypothalamic nucleus controls satiety?
A. Lateral
B. Ventromedial
C. Paraventricular
D. Preoptic

Answer 63

A. Lateral
B. Ventromedial
C. Paraventricular
D. Preoptic

The ventromedial nucleus of the hypothalamus controls satiety. A way to remember this is “if the ventromedial nucleus is destroyed, you grow ventrally and medially.” Further Reading: Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, hypothalamus.

Question 63

Which hypothalamic nucleus is involved in fluid
balance?
A. Lateral
B. Ventromedial
C. Arcuate
D. Supraoptic

Answer 63

A. Lateral
B. Ventromedial
C. Arcuate
D. Supraoptic

The supraoptic nuclei of the hypothalamus are
involved in fluid balance regulation.
Further Reading: Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, hypothalamus.

Question 63

Fibers carrying gustatory information from cranial nerves VII, IX, and X travel between the nucleus
of the solitary tract and VPM thalamus via which
structure?
A. Central tegmental tract
B. Lateral lemniscus
C. Medial lemniscus
D. Trapezoid body

Answer 63

A. Central tegmental tract
B. Lateral lemniscus
C. Medial lemniscus
D. Trapezoid body

Gustatory information from the tongue and
oropharynx travels through the chorda tympani and VIIth nerve, as well as the IX/X nerves. 1st
order neurons synapse in the nucleus of the solitary tract. Then, 2nd order neurons travel via the central tegmental tract to VPM thalamus and 3rd order neurons travel from VPM thalamus to the postcentral gyrus.

Further Reading: Greenstein B, Greenstein A. Color
Atlas of Neuroscience, 2000, transverse section of
medulla oblongata II

Question 63

In order to protect the auditory organs against sudden loud noises, the stapedius and tensor tympani contract to dampen sounds. Which nucleus controls this reflex?
A. Inferior colliculus
B. Superior colliculus
C. Superior olivary nucleus
D. Inferior olivary nucleus

Answer 63

A. Inferior colliculus
B. Superior colliculus
C. Superior olivary nucleus
D. Inferior olivary nucleus

The auditory dampening reflex is mediated by the superior olivary nucleus and involves contraction of the stapedius (VIIth nerve) and tensor tympani (Vth nerve). Further Reading: Psarros. Intensive neurosurgery board review. Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, localization of sound.

Question 64

The cribiform plate is part of which cranial bone?
A. Frontal bone
B. Ethmoid bone
C. Zygomatic bone
D. Nasal bone

Answer 64

A. Frontal bone
B. Ethmoid bone
C. Zygomatic bone
D. Nasal bone

The cribiform plate is a bony structure that is part of the ethmoid bone in the anterior cranial fossa. It supports the olfactory bulb and has numerous foramina through which the olfactory nerves pass to reach the nose. Further Reading: Wanibuchi, Friedman, Fukushima. Photo Atlas of Skull Base Dissection, 2009, craniofacial anatomy

Question 65

Which nerve does not pass through the superior orbital fissure
A. Frontal nerve
B. Maxillary nerve
C. Trochlear nerve
D. Abducens nerve

Answer 65

A. Frontal nerve
B. Maxillary nerve
C. Trochlear nerve
D. Abducens nerve

The maxillary nerve, or V2, does not pass through the superior orbital fissure. Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, clinical and neurologic findings in skull base pathology

Question 66

The vagus nerve exits the base of the skull through what structure?
A. Pars nervosa of the jugular foramen
B. Pars vascularis of the jugular foramen
C. Foramen lacerum
D. Foramen ovale

Answer 66

A. Pars nervosa of the jugular foramen
B. Pars vascularis of the jugular foramen
C. Foramen lacerum
D. Foramen ovale

The vagus nerve exits the skull through the jugular foramen, which is divided into two regions by the jugular spine, the pars nervosa (carrying the glossopharyngeal nerve and inferior petrosal sinus) and the pars vascularis (carrying the jugular bulb, vagus nerve and spinal accessory nerve). Further Reading: Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, vagus nerve

Question 67

You are watching a local slow-pitch softball game and someone is hit in the side of the head with a throw at high velocity. As a neurosurgeon, you are worried about the formation of an epidural hematoma. Through what foramen does the main offending artery enter the skull?
A. Foramen ovale
B. Foramen rotundum
C. Foramen spinosum
D. Foramen lacerum

Answer 67

A. Foramen ovale
B. Foramen rotundum
C. Foramen spinosum
D. Foramen lacerum

The middle meningeal artery is the most common offending artery in cases of epidural hematoma. It enters the skull as a branch from the internal maxillary artery through the foramen spinosum. Further Reading: Wanibuchi, Friedman, Fukushima. Photo Atlas of Skull Base Dissection, 2009, middle fossa rhomboid approach (anterior petrosectomy)

Question 68

The anterior and posterior ethmoidal arteries are branches from which artery?
A. Carotid artery
B. Internal maxillary artery
C. Sphenopalatine artery
D. Ophthalmic artery

Answer 68

A. Carotid artery
B. Internal maxillary artery
C. Sphenopalatine artery
D. Ophthalmic artery

The anterior and posterior ethmoidal arteries give blood supply to the mucosal surfaces of the ethmoid bone, and they are both branches from the ophthalmic artery. Further Reading: Spetzler, Kalani, Nakaji. Neurovascular Surgery, 2nd edition, 2015, microsurgical anatomy of the internal carotid and vertebral arteries

Question 69

During an endoscopic approach to a pituitary tumor, the middle turbinate is removed by the access surgeon. What is the source of blood supply to the middle turbinate?
A. Anterior ethmoid artery
B. Posterior ethmoid artery
C. Kesselbach’s plexus
D. Sphenopalatine artery

Answer 69

A. Anterior ethmoid artery
B. Posterior ethmoid artery
C. Kesselbach’s plexus
D. Sphenopalatine artery

The sphenopalatine artery gives blood supply to the middle turbinate, which can be removed by an access surgeon to allow expanded access for endoscopic approaches to the sella and anterior skull base. Further Reading: Stamm. Transnasal Endoscopic Skull Base and Brain Surgery, 2011, anatomy of the nasal cavity and paranasal sinuses.

Question 70

What structure separates the optic canal from the superior orbital fissure?
A. Optic strut
B. Anterior clinoid process
C. Carotid process
D. Lateral opticocarotid recess

Answer 70

A. Optic strut
B. Anterior clinoid process
C. Carotid process
D. Lateral opticocarotid recess

The optic strut joins the lesser wing of the sphenoid to the body of the sphenoid bone. It forms the inferior and lateral wall of the optic canal. It separates the optic canal from the superior orbital fissure. From an endonasal approach, it is located inferior to the optic protuberence, superiomedial to the carotid protuberence, and medial to the lateral opticocarotid recess. Further Reading: Laws, Sheehan. Sellar and Parasellar Tumors, 2012, anatomy of the sellar and parasellar region.

Question 70

What is the name of the structure located anterosuperior to the sella turcica, but posterior to the ethmoid air cells
A. Optic strut
B. Planum sphenoidale
C. Anterior clinoid process
D. Pterygoid plate

Answer 70

A. Optic strut
B. Planum sphenoidale
C. Anterior clinoid process
D. Pterygoid plate

Just anterosuperior to the sella turcica is the planum sphenoidale. This can be a site of meningioma growth, and tumors in this region can be accessed via an expanded endonasal approach. Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, anatomy of the skull base and related structures: elements of surgical anatomy.

Question 71

The vidian nerve is continuous with which other nerve of the skull base?
A. Lesser superficial petrosal nerve
B. Greater superficial petrosal nerve
C. Nervus intermedius
D. Chorda tympani

Answer 71

A. Lesser superficial petrosal nerve
B. Greater superficial petrosal nerve
C. Nervus intermedius
D. Chorda tympani

The vidian nerve is continuous with the greater superficial petrosal nerve and passes through the vidian canal lateral to the ethmoid air cells. The vidian nerve carries sensory fibers from the facial nerve supplying the soft palate. It is an important landmark in endoscopic endonasal surgery as it leads directly to the carotid artery. Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, anatomy of the skull base and related structures: elements of surgical anatomy.

Question 72

Which foramen is just lateral to the vidian canal?
A. Optic canal
B. Foramen rotundum
C. Foramen ovale
D. Foramen spinosum

Answer 72

A. Optic canal
B. Foramen rotundum
C. Foramen ovale
D. Foramen spinosum

The foramen rotundum is just lateral to the vidian canal and contains the maxillary nerve. Both the vidian canal and foramen rotundum are openings in the greater wing of the sphenoid bone. In this location they connect the middle cranial fossa to the pterygopalatine fossa. Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, anatomy of the skull base and related structures: elements of surgical anatom

Question 73

Which nerve does not run in the double layer of dura making up the lateral wall of the cavernous sinus?
A. Oculomotor nerve
B. Trochlear nerve
C. Ophthalmic nerve
D. Abducens nerve

Answer 73

A. Oculomotor nerve
B. Trochlear nerve
C. Ophthalmic nerve
D. Abducens nerve

The cavernous sinus contains several nerves, including CN III, IV, V1, and VI. All nerves run in the lateral wall of the cavernous sinus except for the abducens nerve, which runs with the carotid artery through the cavernous sinus. Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, anatomy of the skull base and related structures: elements of surgical anatomy.

Question 74

Which triangle of the skull base is bordered by the inferior aspect of the mandibular nerve, the greater superficial petrosal nerve, and a line drawn between the foramen spinosum and the arcuate eminence?
A. Glasscock’s triangle
B. Kawase’s traingle
C. Infratrochlear triangle
D. Trigeminal triangle

Answer 74

A. Glasscock’s triangle
B. Kawase’s traingle
C. Infratrochlear triangle
D. Trigeminal triangle

The posterolateral triangle of the skull base is bordered by V3 (mandibular nerve), the greater superficial petrosal nerve, and a line drawn between the foramen spinosum and the arcuate eminence. This triangle can be important during skull base neurosurgery given that it allows for the exposure of the horizontal segment of the petrous internal carotid artery by drilling out bone inferior to the border of V3. Further Reading: Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, anatomy of the skull base and related structures: elements of surgical anatomy.

Question 75

Which triangle of the skull base is located superior to the greater superficial petrosal nerve, posterior to the mandibular nerve and anterior to the superior petrosal sinus?
A. Glasscock’s triangle
B. Kawase’s traingle
C. Infratrochlear triangle
D. Trigeminal triangle

Answer 75

A. Glasscock’s triangle
B. Kawase’s traingle
C. Infratrochlear triangle
D. Trigeminal triangle

The posteromedial triangle of the skull base is bordered by V3 (mandibular nerve), the greater superficial petrosal nerve (inferiorly), and the superior petrosal sinus. This triangle can be important during skull base neurosurgery given that drilling in this region allows for an anterior petrosectomy, connecting the middle and posterior cranial fossae. It contains the petrous corner of the ICA and in its lateral aspect contains the cochlea. Further Reading: Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, anatomy of the skull base and related structures: elements of surgical anatomy

Question 76

Which triangle of the skull base is bordered by CN IV, CN V1, and the tentorial edge?
A. Glasscock’s triangle
B. Kawase’s traingle
C. Infratrochlear triangle
D. Trigeminal triangle

Answer 76

A. Glasscock’s triangle
B. Kawase’s traingle
C. Infratrochlear triangle
D. Trigeminal triangle

The infratrochlear triangle (Parkinson’s triangle) of the skull base is bordered by the trochlear nerve (superior), V1, and the tentorial edge. This triangle can be important during skull base neurosurgery as it contains the horizontal segment of the cavernous carotid, the abducens nerve and the meningohypophyseal trunk. It has been described as the original access location to the cavernous sinus. Further Reading: Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, anatomy of the skull base and related structures: elements of surgical anatomy

Question 77

Bill’s bar is a structure within the IAC. Which nerves does it separate?
A. Facial nerve–cochlear nerve
B. Superior vestibular nerve–inferior vestibular nerve
C. Facial nerve–superior vestibular nerve
D. Cochlear nerve–inferior vestibular nerve

Answer 77

A. Facial nerve–cochlear nerve
B. Superior vestibular nerve–inferior vestibularvnerve
C. Facial nerve–superior vestibular nerve
D. Cochlear nerve–inferior vestibular nerve

Bill’s bar is a vertically oriented bone within the IAC that separates the Facial nerve (anterosuperior) from the superior vestibular nerve (posterosuperior). The cochlear nerve is located anteroinferior, and the inferior vestibular nerve is located posteroinferior. Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, anatomy of the skull base and related structures: elements of surgical anatomy

Question 78

The abducens, facial, and vestibular nerves are associated with which blood vessel in the posterior fossa?
A. Posterior cerebral artery
B. Superior cerebellar artery
C. Anterior inferior cerebellar artery
D. Posterior inferior cerebellar artery

Answer 78

A. Posterior cerebral artery
B. Superior cerebellar artery
C. Anterior inferior cerebellar artery
D. Posterior inferior cerebellar artery

The posterior fossa can be thought of as three distinct neurovascular regions. The superior region contains CN III, IV, and V, and is associated with the superior cerebellar artery. The middle neurovascular region consists of CN VI, VII, and VIII as well as the anterior inferior cerebellar artery. The inferior neurovascular region contains CN IX, X, XI, and XII, and is associated with the posterior inferior cerebellar artery. Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, anatomy of the skull base and related structures: elements of surgical anatomy

Question 79

Which skull landmark is a rough marker of the location of the transverse-sigmoid sinus junction
A. Bregma
B. Inion
C. Pterion
D. Asterion

Answer 79

A. Bregma
B. Inion
C. Pterion
D. Asterion

The asterion is located where the squamous and parietomastoid sutures join. It is a rough landmark for the transverse sigmoid sinus, and can be an important marker for burr hole location in retrosigmoid craniectomies. Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, anatomy of the skull base and related structures: elements of surgical anatomy.

Question 80

Which is the only cranial nerve to exit on the dorsal aspect of the brainstem?
A. Oculomotor
B. Trochlear
C. Vagus
D. Hypoglossal

Answer 80

A. Oculomotor
B. Trochlear
C. Vagus
D. Hypoglossal

The trochlear nerve is the only cranial nerve to exit from the dorsal aspect of the brainstem. Further Reading: Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, trochlear nerve.

Question 81

The meninges of the skull base arise from which embryological layer?
A. Ectoderm
B. Mesoderm
C. Endoderm
D. Somites

Answer 81

A. Ectoderm
B. Mesoderm
C. Endoderm
D. Somites

The meninges of the skull base arise from the mesoderm of the embryo. This differs from telencephalic meninges which arise from neural crest cells. Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, skull base embryology

Question 82

Which artery travels with cranial nerves VII and VIII in the IAC?
A. Posterior inferior cerebellar artery
B. Calcarine artery
C. Splenial artery
D. Labyrinthine artery

Answer 82

A. Posterior inferior cerebellar artery
B. Calcarine artery
C. Splenial artery
D. Labyrinthine artery

The labyrinthine artery is most commonly a branch from the anterior inferior cerebellar artery, and it follows the vestibulocochlear nerve into the IAC. Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, anatomy of the skull base and related structures: elements of surgical anatomy

Question 83

What is the first intradural branch of the internal carotid artery?
A. Meningohypophyseal trunk
B. Ophthalmic artery
C. Superior hypophyseal artery
D. Posterior communicating artery

Answer 83

A. Meningohypophyseal trunk
B. Ophthalmic artery
C. Superior hypophyseal artery
D. Posterior communicating artery

The ophthalmic artery originates from the internal carotid just distal to the distal dural ring, making it the first intradural branch of the internal carotid artery. Further Reading: Di Ieva, Lee, Cusimano. Handbook of Skull Base Surgery, 2016, anatomy of the skull base and related structures: elements of surgical anatomy.

Question 84

Special visceral afferent fibers from which cranial nerve do not synapse within the thalamus?
A. Facial nerve
B. Hypoglossal nerve
C. Olfactory nerve
D. Trigeminal nerve

Answer 84

Special visceral afferent fibers from which cranial
nerve do not synapse within the thalamus?
A. Facial nerve
B. Hypoglossal nerve
C. Olfactory nerve
D. Trigeminal nerve

Special visceral afferent fibers conveying sense of smell travel through the olfactory nerve directly to the primary olfactory areas via the medial and lateral olfactory striae. Further Reading: Psarros. The Definitive Neurosurgical Board Review. Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, olfactory nerve.

Question 85

Axons of which retinal cells make up the optic nerve?
A. Ganglion cells
B. Bipolar cells
C. Horizontal cells
D. Amacrine cells

Answer 85

A. Ganglion cells
B. Bipolar cells
C. Horizontal cells
D. Amacrine cells

Within the retina, the bioplar cells are the primary sensory neurons. The ganglion cells receive input from bipolar cells, and the axons of the ganglion cells make up the optic nerve. Further Reading: Psarros. The Definitive Neurosurgical Board Review. Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, optic nerve

Question 86

Which muscle is not innervated by the inferior division of the oculomotor nerve?
A. Levator palpebrae
B. Inferior oblique
C. Medial rectus
D. Inferior rectus

Answer 86

A. Levator palpebrae
B. Inferior oblique
C. Medial rectus
D. Inferior rectus

The oculomotor nerve begins within the oculomotor nucleus at the level of the superior colliculus. It travels between the PCA and SCA and enters the orbit through the superior orbital fissure. Notably, it does travel within the annulus of Zinn. It separates into a superior division and inferior division, with the superior division innervating the levator palpebrae and superior rectus, while the inferior division innervates the medial/inferior rectus and the inferior oblique. Further Reading: Psarros. The Definitive Neurosurgical Board Review. Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, oculomotor nerve

Question 87

You are evaluating a patient with a superior oblique palsy, and she leans her head to the left side to compensate for her injury. If the superior oblique palsy is due to damage within the brainstem, which nucleus is involved?
A. Left oculomotor nucleus
B. Right oculomotor nucleus
C. Left trochlear nucleus
D. Right trochlear nucleus

Answer 87

A. Left oculomotor nucleus
B. Right oculomotor nucleus
C. Left trochlear nucleus
D. Right trochlear nucleus

The trochlear nerve innervates the superior oblique muscle, and patients tend to tilt their head to the contralateral side of nerve injury to compensate. Also, the trochlear nerve is the only nerve to deccusate outside of the CNS, and the only cranial nerve to exit dorsally from the brainstem. This patient tilts her head to the left, meaning she would have sustained damage to either the right trochlear nerve (postdecussation), or the left trochlear nucleus (predecussation) Further Reading: Psarros. The Definitive Neurosurgical Board Review. Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, trochlear nerve.

Question 88

Which cranial nerve mediates the efferent component of the auditory reflex via the tensor tympani?
A. Trigeminal nerve
B. Facial nerve
C. Vestibulocohclear nerve
D. Vagus nerve

Answer 88

A. Trigeminal nerve
B. Facial nerve
C. Vestibulocohclear nerve
D. Vagus nerve

The trigeminal nerve has a portio major (sensory afferents from the face) and a portio minor (motor efferents) that travels with V3. The motor branch of the trigeminal nerve innervates the muscles of mastication, including the tensor veli palatini, masseter, pterygoids, temporalis and anterior belly of the digastric. It also innervates the tensor tympani, which dampens sudden loud noises in the efferent arm of the auditory reflex. Further Reading: Psarros. The Definitive Neurosurgical Board Review. Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, trigeminal nerve

Question 89

You are evaluating a patient who has a lateral gaze palsy of the right eye. During your exam you also notice that the patient cannot cross midline with the left eye on attempted right lateral gaze. Where is the lesion?
A. Left oculomotor nerve
B. Left oculomotor nucleus
C. Right abducens nerve
D. Right abducens nucleus

Answer 89

A. Left oculomotor nerve
B. Left oculomotor nucleus
C. Right abducens nerve
D. Right abducens nucleus

The abducens nerve innervates the lateral rectus muscle and mediates lateral gaze of the ipsilateral eye. It is important to note that the abducens nucleus plays an important role in conjuage movement of the eyes. Signals initially reach the ipsilateral PPRF, which synapses on the ipsilateral abducens nucleus to mediate lateral gaze. The abducens nucleus also sends fibers to the contralateral oculomotor nucleus via the MLF to mediate conjugate medial deviation of the contralateral eye. Since this patient cannot cross midline with the left eye, the lesion must be within the abducens nucleus. Further Reading: Psarros. The Definitive Neurosurgical Board Review. Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, abducens nerve.

Question 90

The nervus intermedius carries fibers for all of the following except?
A. Efferent arm of the corneal reflex
B. Parasympathetic efferents to the lacrimal gland
C. Parasympathetic efferents to the submandibular gland
D. Taste from the anterior two-thirds of the tongue

Answer 90

A. Efferent arm of the corneal reflex
B. Parasympathetic efferents to the lacrimal
gland
C. Parasympathetic efferents to the submandibular gland
D. Taste from the anterior two-thirds of the tongue

The facial nerve contains a large motor branch as well as a smaller branch known as the nervus intermedius. The motor branch controls muscles of facial expression and forehead. The nervus intermedius carries parasympathetic fibers to the lacrimal gland through the GSPN and pterygopalatine ganglion, parasympathetic fibers to the submandibular gland via the submandibular ganglion, and taste afferents via the chorda tympani. The efferent arm of the corneal reflex is mediated by muscles of facial expression and is carried in the motor branch of the facial nerve. Further Reading: Psarros. The Definitive Neurosurgical Board Review. Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, facial nerve.

Question 91

The cochlear nerve connects which ganglion to which nucleus?
A. Spiral–vestibular nuclei
B. Spiral–cochlear
C. Scarpa’s–cochlear
D. Scarpa’s–vestibular nuclei

Answer 91

A. Spiral–vestibular nuclei
B. Spiral–cochlear
C. Scarpa’s–cochlear
D. Scarpa’s–vestibular nuclei

Hair cells from the organ of Corti within the cochlea synapse on the spiral ganglion, which in turn connects to the cochlear nucleus in the brainstem via the cochlear nerve. Scarpa’s ganglion receives input from the receptors in the labyrinth of the saccule, utricle and semicircular canals. In turn, these fibers are transmitted to the vestibular nuclei of the brainstem via the vestibular nerve. Some fibers from Scarpa’s ganglion travel to the flocculonodular lobe of the cerebellum as mossy fibers, where they mediate balance. Further Reading: Psarros. The Definitive Neurosurgical Board Review. Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, vestibulocochlear nerve.

Question 92

The glossopharyngeal nerve mediates salivation from the parotid gland via which nerve?
A. Lesser superficial petrosal nerve
B. Greater superficial petrosal nerve
C. Vidian nerve
D. Chorda tympani

Answer 92

A. Lesser superficial petrosal nerve
B. Greater superficial petrosal nerve
C. Vidian nerve
D. Chorda tympani

The glossopharyngeal nerve innervates the parotid gland via branches that form the lesser superficial petrosal nerve. The lesser superficial petrosal nerve contains preganglionic parasympathetic nerves from the inferior salivatory nucleus of the brainstem that synapse in the otic ganglion. In turn, postganglionic parasympathetic nerves leave the otic ganglion and travel to the parotid gland via the auriculotemporal nerve (traveling with V3). Further Reading: Psarros. The Definitive Neurosurgical Board Review. Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, glossopharyngeal nerve.

Question 93

Which muscle is not innervated by the recurrent branch of the laryngeal nerve?
A. Transverse arytenoid
B. Thyroepiglottic
C. Posterior cricoarytenoid
D. Cricothyroid

Answer 93

A. Transverse arytenoid
B. Thyroepiglottic
C. Posterior cricoarytenoid
D. Cricothyroid

The recurrent laryngeal nerve is a branch from the vagus nerve that passes anterior to the subclavian artery on the right, and adjacent to the aorta on the left. Its recurrent route traverses in the tracheoesophageal groove. It innervates all intrinsic muscles of the larynx with the exception of the cricothyroid muscle. Further Reading: Psarros. The Definitive Neurosurgical Board Review. Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, vagus nerve

Question 94

The spinal portion of the spinal accessory nerve passes in what location relative to the dentate ligamameng
A. Anterior
B. Medial
C. Posterior
D. Lateral

Answer 94

A. Anterior
B. Medial
C. Posterior
D. Lateral

The spinal accessory nerve has both a cranial and spinal point of origination. It innervates the sternocleidomastoid and trapezius muscles. The spinal portion passes posterior to the dentate ligament. Further Reading: Psarros. The Definitive Neurosurgical Board Review. Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, spinal accessory nerve.

Question 95

Which extrinsic muscle of the tongue is not innervated by the hypoglossal nerve
A. Palatoglossus
B. Styloglossus
C. Genioglossus
D. Hyoglossus

Answer 95

A. Palatoglossus
B. Styloglossus
C. Genioglossus
D. Hyoglossus

The hypoglossal nerve exits the brainstem between the inferior olive and the pyramids. It exits the skull via the hypoglossal canal and innervates all intrinsic and extrinsic muscles of the tongue except for the palatoglossus, which is innervated by the vagus nerve. Further Reading: Psarros. The Definitive Neurosurgical Board Review. Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, hypoglossal nerve.

Question 96

The motor root of the trigeminal nerve arises where in relation to the main sensory root of the trigeminal nerve?
A. Caudal
B. Posterior
C. Lateral
D. Rostral

Answer 96

A. Caudal
B. Posterior
C. Lateral
D. Rostral

The motor root of the trigeminal nerve most often arises rostral to the main sensory root of the trigeminal nerve. Further Reading: Binder, Sonne, Fischbein. Cranial Nerves: Anatomy, Pathology, Imaging, 2010, trigeminal nerve.

Question 97

This structure connects the upper border of C1 to the foramen magnum?
A. Apical ligament
B. Posterior atlanto-occipital membrane
C. Tectorial membrane
D. Anterior atlanto-occipital membrane

Answer 97

A. Apical ligament
B. Posterior atlanto-occipital membrane
C. Tectorial membrane
D. Anterior atlanto-occipital membrane

The anterior atlanto-occipital membrane connects the anterosuperior border of C1 to the foramen magnum. Further Reading: Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, craniovertebral junction

Question 98

The single structure connecting the dens to the foramen magnum is a remnant of what embryological structure?
A. Alar plate
B. Notochord
C. Basal plate
D. Neural tube

Answer 98

A. Alar plate
B. Notochord
C. Basal plate
D. Neural tube

The apical ligament is a single structure connecting the dens to the foramen magnum. It is a weak ligament that is an embryological remnant of the notochord. Further Reading: Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, embryology of the spine.

Question 99

These paired ligaments in the cervical spine are strong ligaments that restrict rotation of the head?
A. Alar
B. Apical
C. Transverse
D. Cruciate

Answer 99

A. Alar
B. Apical
C. Transverse
D. Cruciate

The alar ligaments are paired ligaments that connect the tip of the dens to the foramen magnum near the occipital condyles. They are strong ligaments that limit rotation of the head. Further Reading: Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, craniovertebral junction.

Question 100

You are evaluating a 79-year-old man who slipped, fell, and hit his head on the sidewalk. He had the onset of neck pain and presented to the ED in a cervical collar. On CT scan of the cervical spine, you see that the dens is indenting the upper cervical spinal cord and the atlanto-dental interval is significantly increased > 3 mm. Which structure is clearly damaged?
A. Alar ligament
B. Apical ligaments
C. Transverse ligament
D. Cruciate ligament

Answer 100

A. Alar ligament
B. Apical ligaments
C. Transverse ligament
D. Cruciate ligament

The transverse ligament is a strong ligament that is very important in stability of the atlanto-axial joint. When the atlanto-dental interval is > 3 mm, this is highly suggestive of transverse ligament disruption and instability of the C1-2 joint. Surgical stabilization or prolonged collar immobilization will likely be required. Further Reading: Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, craniovertebral junction

Question 101

The tectorial membrane of the cervical spine is the superior continuation of which spinal structure?
A. Anterior longitudinal ligament
B. Posterior longitudinal ligament
C. Intertransverse ligament
D. Supraspinous ligament

Answer 101

A. Anterior longitudinal ligament
B. Posterior longitudinal ligament
C. Intertransverse ligament
D. Supraspinous ligament

The tectorial membrane is a broad ligament connecting the axis to the clivus/foramen magnum, and is a superior extension of the posterior longitudinal ligament. Further Reading: Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, craniovertebral junction

Question 102

You decided to offer a C1-2 fusion for a 70-year-old man with an unstable Type II odontoid fracture. Prior to the start of your procedure, which structure should you evaluate at C2 that may change your fusion technique?
A. Carotid artery
B. Vertebral artery
C. C2 nerve root
D. Recurrent laryngeal nerve

Answer 102

A. Carotid artery
B. Vertebral artery
C. C2 nerve root
D. Recurrent laryngeal nerve

The vertebral artery can have variant anatomy within the C2 vertebrae. Certain patients can have a “high-riding vertebral artery” where the vessel passes in close proximity to the C2 pedicle. In these patients it can be dangerous to attempt pedicle screws at C2, and pars screws or interlaminar screws should be considered. In most cases, a high riding vertebral artery can be discovered with a standard, non-contrast CT of the cervical spine in the pre-operative period. Further Reading: Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, craniovertebral junction

Question 103

Which anatomical variant is associated with atlantoaxial instability?
A. Split anterior arch of atlas
B. Split posterior arch of atlas
C. Os odontoideum
D. Klippel-Feil syndrome

Answer 103

A. Split anterior arch of atlas
B. Split posterior arch of atlas
C. Os odontoideum
D. Klippel-Feil syndrome

Os odontoideum is either a congenital failure of fusion of the dens to the C2 vertebral body, or an unrecognized fracture at a young age. When the pseudoarthrosis is present inferior to the transverse ligament, atlantoaxial instability can result. Further Reading: Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, Craniovertebral Junction

Question 104

The first ossification centers of the spine develop in utero at the cervicothoracic junction. What week of development does the first ossification center develop?
A. 6 weeks
B. 9 weeks
C. 12 weeks
D. 15 weeks

Answer 104

A. 6 weeks
B. 9 weeks
C. 12 weeks
D. 15 weeks

The first ossification centers of the spine tend to occur at the cervicothoracic junction, and begin to appear at 9 weeks in utero. Further Reading: Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, embryology of the spine

Question 105

You are evaluating a 2-year-old for suspected non-accidental trauma in the emergency department. The radiology resident read the CT scan of the cervical spine and reported the presence of three fractures through the atlas consistent with a Jefferson-type fracture. You believe these are ossification centers. At what age are most posterior ossification centers of the atlas closed?
A. 6 months
B. 1 year
C. 3 years
D. 6 years

Answer 105

A. 6 months
B. 1 year
C. 3 years
D. 6 years

The atlas is composed of three main ossification centers, one anteriorly, and two posteriorly. It is common for the posterior ossification centers to persist until 3 years of age, while the anterior ossification center can persist even until 7 years of age. These ossification centers can easily be mistaken for acute fractures. Further Reading: Lustrin et al. 2003, Pediatric Cervical Spine: Normal Anatomy, Variants, and Trauma. Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, embryology of the spine.

Question 106

You are seeing an 8-year-old boy in the emergency department. He was brought in after playing tackle football. He was hit and developed neck pain. The CT scan of the cervical spine was read as possible type II odontoid fracture. You believe the findings are consistent with normal development. At what age should the ossification centers of the axis no longer be visible?
A. 7 years
B. 9 years
C. 11 years
D. 13 years

Answer 106

A. 7 years
B. 9 years
C. 11 years
D. 13 years

The axis undergoes complicated ossification in 4 different ossification centers. The subdental synchondrosis, or the region where the dens attaches to the body of the axis is usually the last center to be visible on CT scans. It should be completely closed and no longer significantly visible by 11 years of age. Further Reading: Lustrin et al., 2003, Pediatric Cervical Spine: Normal Anatomy, Variants, and Trauma. Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, embryology of the spine

Question 107

In the developing embryo, which structure divides the alar plate from the basal plate?
A. Median eminence
B. Sulcus limitans
C. Neural groove
D. Henson’s node

Answer 107

A. Median eminence
B. Sulcus limitans
C. Neural groove
D. Henson’s node

The developing embryo has both a basal plate and an alar plate. The basal plate develops into motor neurons, while the alar plate develops into sensory neurons. The structure dividing them is the sulcus limitans. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, embryology of the spine.

Question 108

During embryologic development, failure of separation of neural ectoderm from superficial ectoderm leads to what pathology?
A. Dermal sinus tract
B. Myelomeningocele
C. Split-cord malformation
D. Spinal cord lipoma

Answer 108

A. Dermal sinus tract
B. Myelomeningocele
C. Split-cord malformation
D. Spinal cord lipoma

During embryologic development, disjunction occurs when the surface ectoderm separates from the neural ectoderm. Failure of disjunction can lead to the development of dermal sinus tracts. Premature disjunction can lead to the development of spinal cord lipomas. Further Reading: Psarros. The definitive neurological surgery board review. Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, congenital and neuromuscular scoliosis.

Question 109

During embryologic development, somites develop from the paraxial mesoderm at what days of development?
A. 15 to 17
B. 19 to 21
C. 23 to 25
D. 27 to 29

Answer 109

A. 15 to 17
B. 19 to 21
C. 23 to 25
D. 27 to 29

Somites form from paraxial mesoderm adjacent to the notocord. They begin initially in the cervical region and progress caudally. They begin forming between days 19 to 21 of development. Further Reading: Psarros. The Definitive Neurological Surgery Board Review Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, embryology of the spine.

Question 110

During embryologic development, somites differentiate into what structures?
A. Motor neurons
B. Sympathetic ganglia
C. Vertebral column and spinal musculature
D. Intervertebral discs

Answer 110

A. Motor neurons
B. Sympathetic ganglia
C. Vertebral column and spinal musculature
D. Intervertebral discs

Somites form from paraxial mesoderm adjacent to the notocord. They begin initially in the cervical region and progress caudally. They begin forming between days 19 to 21 of development. Ultimately they develop into the vertebral column and dorsal spinal musculature. Their rate of growth exceeds that of the spinal cord, which is why the cord ascends in the canal during development. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, embryology of the spine.

Question 111

The sacral spinal cord is developed during which embryologic process?
A. Primary neurulation
B. Secondary neurulation
C. Disjunction
D. Cell migration

Answer 111

A. Primary neurulation
B. Secondary neurulation
C. Disjunction
D. Cell migration

The sacral spinal cord (distal to S2) is formed during secondary neurulation. Failure of this process can lead to caudal regression syndromes. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, embryology of the spine.

Question 112

Sensory information from above T6 travels in what structure within the spinal cord?
A. Fasciculus cuneatus
B. Fasuculus gracilis
C. Ventral corticospinal tract
D. Dorsal spinocerebellar tract

Answer 112

A. Fasciculus cuneatus
B. Fasuculus gracilis
C. Ventral corticospinal tract
D. Dorsal spinocerebellar tract

The fibers carrying sensory information travel within the dorsal columns. Fibers entering above T6 travel within the fasciculus cuneatus, just lateral to the fasciculus gracilis, which carries fibers from below T6. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, an

Question 113

Which rexed lamina lies between the dorsal and ventral horns of the spinal cord?
A. Lamina II
B. Lamina V
C. Lamina VII
D. Lamina IX

Answer 113

A. Lamina II
B. Lamina V
C. Lamina VII
D. Lamina IX

Lamina VII (Zona intermedia) is the rexed lamina located between the dorsal and ventral horns. The dorsal horn contains lamina I-IV, which V and VI at its base. The ventral horn contains VIII-X. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, Sensory Fibers and Dorsal Roots.

Question 114

The substantia gelatinosa is located in which rexed lamina?
A. Lamina II
B. Lamina V
C. Lamina VII
D. Lamina IX

Answer 114

A. Lamina II
B. Lamina V
C. Lamina VII
D. Lamina IX

The substantia gelatinosa is located in rexed lamina II and due to its lower density of myelinated fibers, it has a gelatinous appearance. It is one of two locations (the nucleus proprius being the other) where first order neurons of the spinothalamic tract synapse. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, sensory fibers and dorsal roo

Question 115

The interomediolateral cell column and dorsal nucleus of Clarke are located in which lamina of the spinal cord?
A. Lamina II
B. Lamina V
C. Lamina VII
D. Lamina IX

Answer 115

A. Lamina II
B. Lamina V
C. Lamina VII
D. Lamina IX

Lamina VII (Zona intermedia) is the rexed lamina located between the dorsal and ventral horns. Lamina VII contains the interomediolateral cell column and dorsal nucleus of Clarke. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, sensory fibers and dorsal roots.

Question 116

Renshaw cells of the spine are located in which rexed lamina?
A. Lamina II
B. Lamina V
C. Lamina VII
D. Lamina IX

Answer 116

A. Lamina II
B. Lamina V
C. Lamina VII
D. Lamina IX

Renshaw cells are special inhibitory interneurons of the spinal cord. They are mainly located in rexed laminae VII and VIII and they use glycine as a neurotransmitter. Further Reading: Psarros. The definitive neurological surgery board review. Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, sensory fibers and dorsal roots.

Question 117

Primary motor neurons are located in which rexed lamina?
A. Lamina II
B. Lamina V
C. Lamina VII
D. Lamina IX

Answer 117

A. Lamina II
B. Lamina V
C. Lamina VII
D. Lamina IX

Primary somatic motor neurons are located in lamina IX and are composted of medial and lateral groups. The medial group innervates axial musculature while the lateral group innervates appendicular musculature. Further Reading: Greenstein B, Greenstein A. Color Atlas of Neuroscience, 2000, sensory fibers and dorsal roots.

Question 118

Pain and temperature sensation from the peripheral nervous system is conveyed through which spinal cord tract?
A. Anterior spinothalamic tract
B. Lateral spinothalamic tract
C. Dorsal spinocerebellar tract
D. Lateral corticospinal tract

Answer 118

A. Anterior spinothalamic tract
B. Lateral spinothalamic tract
C. Dorsal spinocerebellar tract
D. Lateral corticospinal tract

Pain and temperature information is transmitted to the CNS via the lateral spinothalamic tract, while the anterior spinothalamic tract conveys information about light touch. Further Reading: Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatomy

Question 119

Second order ascending neurons originating in Clarke’s nucleus travel in which spinal cord tract?
A. Anterior spinothalamic tract
B. Lateral spinothalamic tract
C. Dorsal spinocerebellar tract
D. Ventral spinocerebellar tract

Answer 119

A. Anterior spinothalamic tract
B. Lateral spinothalamic tract
C. Dorsal spinocerebellar tract
D. Ventral spinocerebellar tract

The dorsal spinocerebellar tract contains sensory information originating in group Ia, Ib and II afferent fibers of the peripheral system. They synapse in the dorsal nucleus of Clarke (C8-L2) and travel to the cerebellum through the dorsal spinocerebellar tract where they enter the cerebellum via the inferior cerebellar peduncle and synapse within the vermis. They are involved in unconscious balance and proprioception mechanisms. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anato

Question 120

You are falling asleep during neurosurgery teaching rounds and your co-resident pinches the back of your left arm. You immediately wake up and turn your head to the left to see what caused the pain. Which spinal cord tract is involved, causing you to turn and look at the source of the pain?
A. Lateral reticulospinal tract
B. Spinotectal tract
C. Lateral corticospinal tract
D. Ventral corticospinal tract

Answer 120

A. Lateral reticulospinal tract
B. Spinotectal tract
C. Lateral corticospinal tract
D. Ventral corticospinal tract

The spinotectal tract has its origins from lamina I and V of the dorsal horn and projects to the superior colliculus and periacqueductal grey in close proximity to the spinothalamic system. It is involved in reflexive head turning to focus on a source of painful stimulus. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatom

Question 121

What percentage of corticospinal tract fibers originate from the large Betz pyramidal cells of the motor cortex?
A. 3%
B. 10%
C. 30%
D. 100%

Answer 121

A. 3%
B. 10%
C. 30%
D. 100%

Only 3% of the corticospinal tract fibers originate from the giant pyramidal Betz cells in the motor cortex. Roughly 40% originate in the parietal lobe, roughly 30% originate in the supplementary motor area, and 30% originate in the primary motor cortex. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatomy.

Question 122

In which rexed lamina do the majority of lateral corticospinal fibers synapse?
A. Lamina II
B. Lamina V
C. Lamina VII
D. Lamina IX

Answer 122

A. Lamina II
B. Lamina V
C. Lamina VII
D. Lamina IX

The majority of lateral corticospinal tract fibers snyapse primarily on interneurons in lamina VII. Only a minority of fibers synapse directly on alpha motor neurons of the anterior horn. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatom

Question 123

You are evaluating a patient in the neuro ICU who has bithalamic compression from a very large subdural hematoma. She is comatose and is exhibiting decorticatae posturing. What nonpyramidal spinal tract mediates this response?
A. Vestibulospinal tract
B. Rubrospinal tract
C. Reticulospinal tract
D. Medial longitudinal fasciculus

Answer 123

A. Vestibulospinal tract
B. Rubrospinal tract
C. Reticulospinal tract
D. Medial longitudinal fasciculus

The rubrospinal tract contains fibers descending from the red nucleus and mediates flexor tone in the response to deep painful stimulus to the extremities. In a patient with decorticate (flexor) posturing, the red nucleus remains intact and flexor tone is maintained. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anat

Question 124

You are evaluating a patient in the emergency department who is comatose from a large subdural hematoma. He demonstrates decerebrate posturing and fixed, nonreactive pupils. What spinal cord tract mediates his peripheral response?
A. Vestibulospinal tract
B. Rubrospinal tract
C. Reticulospinal tract
D. Medial longitudinal fasciculus

Answer 124

A. Vestibulospinal tract
B. Rubrospinal tract
C. Reticulospinal tract
D. Medial longitudinal fasciculus

The vestibulospinal tract begins in Dieter’s nucleus (vestibular nucleus) and descends to rexed lamina VII, VIII, and IX. Occasionally, fibers will synapse directly on alpha motor neurons. This nucleus and tract mediate extensor tone of the extremities and is usually under tonic inhibition by higher brain centers. With a lesion between the superior and inferior colliculi, the vestibular nucleus is released from its inhibition and extensor posturing (decerebrate) is observed. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anat

Question 125

Which spinal cord tract mediates postural reflexes responsive to visual and auditory stimuli?
A. Vestibulospinal tract
B. Rubrospinal tract
C. Reticulospinal tract
D. Tectospinal tract

Answer 125

A. Vestibulospinal tract
B. Rubrospinal tract
C. Reticulospinal tract
D. Tectospinal tract

The tectospinal tract carries information from the superior colliculus to all levels of the cervical cord. It mediates postural reflexes and movement of the upper body in response to visual and auditory stimuli. Further Reading: Psarros. The Definitive Neurological Surgery Board Review Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatom

Question 126

What uncrossed pyramidal tract fibers descend adjacent to the anterior median fissure of the spinal cord and decussate via the anterior commissure in upper cervical levels?
A. Lateral corticospinal tract
B. Anterolateral corticospinal tract
C. Anterior corticospinal tract
D. Vestibulospinal tract

Answer 126

A. Lateral corticospinal tract
B. Anterolateral corticospinal tract
C. Anterior corticospinal tract
D. Vestibulospinal tract

90% of descending pyramidal tract fibers travel in the lateral corticospinal tracts. A small number of uncrossed fibers travel in the anterior corticospinal tract, which is located near the median fissure of the cervical spinal cord. In the upper cervical levels they decussate via the anterior commissure and synapse within lamina VII. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatomy

Question 127

The blood supply to the dorsal columns of the spinal cord descends longitudinally in which orientation compared to the dorsal roots?
A. Lateral
B. Medial
C. Superior
D. Inferior

Answer 127

A. Lateral
B. Medial
C. Superior
D. Inferior

The dorsal columns of the spinal cord receive blood supply from the paired posterior spinal arteries, which lie medial to the dorsal roots, and generally originate from multiple posterior radicular arteries. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatom

Question 128

The cervical spinal cord receives the majority of its blood supply from which originating vessels?
A. Anterior radicular arteries
B. Posterior radicular arteries
C. Vertebral arteries
D. Carotid arteries

Answer 128

A. Anterior radicular arteries
B. Posterior radicular arteries
C. Vertebral arteries
D. Carotid arteries

The anterior spinal arteries originate from the vertebral arteries and fuse in the midline to form the single anterior spinal artery traversing the cervical cord in the median fissure. It supplies the majority of the cervical spinal cord. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatomy

Question 129

Which segment of the spinal cord is the most susceptible to ischemic injury?
A. C3-C7
B. T1-T4
C. L1-L4
D. Conus medullaris

Answer 129

A. C3-C7
B. T1-T4
C. L1-L4
D. Conus medullaris

The upper thoracic region (T1-T4) is the most susceptible region of the spinal cord to ischemic injury. It is followed by the first lumbar segment, which is the next most susceptible. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatom

Question 130

Which spinal cord segment is most likely to contain the artery of Adamkiewicz?
A. Left T2
B. Right T2
C. Left T10
D. Right T10

Answer 130

A. Left T2
B. Right T2
C. Left T10
D. Right T10

The artery of Adamkiewicz is a large lower thoracic/upper lumbar anterior radicular artery that supplies the anterior spinal artery and the anterior spinal cord of the thoracic/lumbar regions. Injury to this artery can result in an anterior spinal artery infarct and paraplegia. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatom

Question 131

You have evaluated a 30-year-old woman with progressive lower extremity weakness and urinary incontinence. Imaging demonstrates T2 signal change in the spinal cord over multiple levels and is suggestive of tortuous vessels. On vascular imaging a spinal cord dAVF on the left at T12 is discovered. You decide to treat with endovascular coiling. If you inadvertently occlude the artery of Adamkiewicz, what deficit would you expect the patient to have?
A. Ipsilateral paraplegia, contralateral loss of pinprick sensation, ipsilateral loss of pain/ temperature sensation
B. Preserved strength, bilateral loss of pinprick sensation, preserved pain/temperature sensation
C. Paraplegia, ipsilateral loss of pinprick sensation, contralateral loss of pain/temperature sensation
D. Paraplegia, preserved pinprick sensation, bilateral loss of pain/temperature sensation

Answer 131

A. Ipsilateral paraplegia, contralateral loss of pinprick sensation, ipsilateral loss of pain/temperature sensation
B. Preserved strength, bilateral loss of pinprick sensation, preserved pain/temperature sensation
C. Paraplegia, ipsilateral loss of pinprick sensation, contralateral loss of pain/temperature sensation
D. Paraplegia, preserved pinprick sensation, bilateral loss of pain/temperature sensation

The artery of Adamkiewicz is a large lower thoracic/upper lumbar anterior radicular artery that supplies the anterior spinal artery and the anterior spinal cord of the thoracic/lumbar regions. Injury to this artery can result in an anterior spinal artery syndrome which includes paraplegia and loss of pain/temperature sensation with preserved pinprick sensation as the dorsal columns are supplied by the posterior spinal arteries. Further Reading: Psarros. The Definitive Neurological Surgery Board Review. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anat

Question 132

You are evaluating a 65-year-old man who had the onset of severe, radiating right leg pain down to his knee. On physical exam, he has weakness of knee extension. If his pathology is a paramedian herniated lumbar disc, what level is it most likely to be at?
A. L2-3
B. L3-4
C. L4-5
D. L5-S1

Answer 132

A. L2-3
B. L3-4
C. L4-5
D. L5-S1

Pain to the knee and weakness of the quadriceps is usually due to a herniated lumbar disc at L3-4. These symptoms are 99% specific for a disc at this level. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, lumbar and thoracic intervertebral disk herniation/radiculopathy

Question 133

You are evaluating a 45-year-old woman who had the onset of severe, radiating right leg pain down to her ankle. On physical exam, she has weakness of ankle dorsiflexion. If her pathology is a herniated lumbar disc, what level is it most likely to be at
A. L2-3
B. L3-4
C. L4-5
D. L5-S1

Answer 133

A. L2-3
B. L3-4
C. L4-5
D. L5-S1

Pain to the ankle and weakness of ankle dorsiflexion is usually due to a herniated lumbar disc at L4-5, and this constellation of symptoms is 70% specific for a disc at this level. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, lumbar and thoracic intervertebral disk herniation/radiculopathy

Question 134

You are evaluating a 45-year-old woman who had the onset of severe, radiating right leg pain down the back of her thigh. On physical exam, she has weakness of ankle plantarflexion. If her pathology is a herniated lumbar disc, what level is it most likely to be at?
A. L1-2
B. L3-4
C. L4-5
D. L5-S1

Answer 134

A. L2-3
B. L3-4
C. L4-5
D. L5-S1

Pain to the ankle and weakness of ankle plantarflexion is usually due to a herniated lumbar disc at L5-S1, and this constellation of symptoms is 95% specific for a disc at this level. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, lumbar and thoracic intervertebral disk herniation/radiculopathy.

Question 135

You are evaluating a 40-year-old woman who had the onset of severe, radiating right leg pain to the top of her ankle. On physical exam, she has weakness of ankle dorsiflexion. If her pathology is a herniated lumbar disc, where would you expect the herniation to be?
A. Paracentral L3-4
B. Paracentral L4-5
C. Far lateral L2-3
D. Far lateral L3-4

Answer 135

A. Paracentral L3-4
B. Paracentral L4-5
C. Far lateral L2-3
D. Far lateral L3-4

This constellation of symptoms is suggestive of L5 nerve root impingement. This is possible with a paracentral disc at L4-5, compressing the traversing root, or possible with a far lateral L5-S1 disc, compressing the exiting nerve root. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, lumbar and thoracic intervertebral disk herniation/radiculopathy.

Question 136

You are evaluating a 40-year-old woman who had the onset of severe, radiating right leg pain to her ankle. On physical exam, she has some weakness of ankle dorsiflexion, but obvious weakness of EHL function. If her pathology is a herniated lumbar disc, where would you expect the herniation to be?
A. Paracentral L3-4
B. Far lateral L4-5
C. Paracentral L5-S1
D. Far lateral L5-S1

Answer 136

A. Paracentral L3-4
B. Far lateral L4-5
C. Paracentral L5-S1
D. Far lateral L5-S1

This constellation of symptoms is suggestive of L5 nerve root impingement. This is possible with a paracentral disc at L4-5, compressing the traversing root, or possible with a far lateral L5-S1 disc, compressing the exiting nerve root. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, lumbar and thoracic intervertebral disk herniation/radiculopathy

Question 137

You are evaluating a 50-year-old man who had the onset of severe, radiating left neck pain to his shoulder. On physical exam, he has weakness of his shoulder with patchy sensory loss of the shoulder as well. If his pathology is a herniated cervical disc, what level do you expect it to be?
A. C2-3
B. C3-4
C. C4-5
D. C5-6

Answer 137

A. C2-3
B. C3-4
C. C4-5
D. C5-6

You must remember that in the cervical spine, nerve roots exit above the corresponding vertebral body, with the exception of C8, which exits under the C7 vertebral body. This patient has symptoms suggestive of a disc herniation compressing the C5 nerve root, meaning the herniation is likely to be located at the C4-5 space. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, cervical disc herniatio

Question 138

You are evaluating a 50-year-old man who has a herniated cervical disc on the right at C5-6, where would you expect him to have sensory loss on exam?
A. Right shoulder
B. Right thumb
C. Right third finger
D. Right 5th finger

Answer 138

A. Right shoulder
B. Right thumb
C. Right third finger
D. Right 5th finger

In this patient with a herniated disc at the C5-6 space, there should be compression of the exiting C6 nerve root. The sensory distribution of C6 includes the radial forearm and thumb as well as the 2nd finger. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, cervical disc herniatio

Question 139

You are evaluating a 50-year-old man who has a herniated cervical disc on the right at C6-7, where would you expect him to have weakness on exam?
A. Right shoulder
B. Right wrist flexion
C. Right wrist extension
D. Right finger extension

Answer 139

A. Right shoulder
B. Right wrist flexion
C. Right wrist extension
D. Right finger extension

In this patient with a herniated disc at the C6-7 space, there should be compression of the exiting C7 nerve root. C7 compression can lead to triceps weakness as well as weakness of wrist flexion. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, cervical disc herniation

Question 140

You are evaluating a 50-year-old man who has a herniated cervical disc on the right at C7-T1, where would you expect him to have weakness on exam?
A. Right interossei
B. Right wrist flexion
C. Right wrist extension
D. Right distal finger flexion

Answer 140

A. Right interossei
B. Right wrist flexion
C. Right wrist extension
D. Right distal finger flexion

In this patient with a herniated disc at the C6-7 space, there should be compression of the exiting C8 nerve root. C8 compression can lead to weakness of the distal finger flexors as well as parasthesias of the 4th and 5th digits. Further Reading: Greenberg. Handbook of Neurosurgery, 8th edition, 2016, cervical disc herniation

Question 141

You are evaluating a 50-year-old man who has had difficulty walking as he gets pain in his back and legs when standing up. MR imaging demonstrates spinal stenosis at L4-5. On exam he has four-fifth strength in bilateral hip flexors with clonus and a positive Hoffman’s sign. What is your next step?
A. L4-5 decompressive laminectomy
B. Lower extremity EMG
C. Cervical MRI
D. Physical therapy and pain control

Answer 141

A. L4-5 decompressive laminectomy
B. Lower extremity EMG
C. Cervical MRI
D. Physical therapy and pain control

This patient presents with symptoms suggestive of pseudoclaudication, with leg pain/weakness when upright as well as evidence of spinal stenosis at L4-5 on MRI. On exam, he has the above mentioned weakness, but also has a positive Hoffman’s sign, a reflex suggestive of cervical compression. This patient should undergo cervical MRI to rule out presence of tandem stenosis. It may be that his symptoms are generated from cervical stenosis, and further workup is required. Further Reading: Harbaugh, Shaffrey, Couldwell, Berger. Neurosurgery Knowledge Update, 2015, pathophysiology of axial spinal pain, radiculopathy, and myelopathy.

Question 142

You are evaluating a 50-year-old man who has been found to have osteomyelitis as a complication from ongoing pyelonephritis. Which structure is theorized to allow spread of pelvic infections to the spine?
A. Lumbar nerve roots
B. Batson’s plexus
C. Thoracic duct
D. Artery of Adamkiewicz

Answer 142

A. Lumbar nerve roots
B. Batson’s plexus
C. Thoracic duct
D. Artery of Adamkiewicz

Batson’s plexus is a venous plexus in the epidural spinal compartment that is continuous with pelvic venous systems. It is unique in that this venous system does not contain valves. It is theorized that the lack of valves allow for easier transfer of both bacterial infections as well as metastatic lesions to affect the spine and spinal cord. Further Reading: Spetzler, Kalani, Nakaji. Neurovascular Surgery, 2nd edition, 2015, spinal vascular anatom

Question 143

The nucleus pulposus of the intervertebral disc is derived from what embryological origin?
A. Somites
B. Neural crest cells
C. Notochord
D. Neural tube

Answer 143

A. Somites
B. Neural crest cells
C. Notochord
D. Neural tube

The nucleus pulposus of the intervertebral disc is an embryological remnant of the notochord Further Reading: Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, embryology of the spine

Question 144

Which ligament of the spine is noncontiguous?
A. Supraspinous ligament
B. Ligamentum flavum
C. Posterior longitudinal ligament
D. Anterior longitudinal ligament

Answer 144

B. Ligamentum flavum

The ligamentum flavum is a non-contiguous ligament that connects laminae between segments. It helps to provide tension when the spine is in flexion, to avoid flexion injuries under normal loads. It has a high proportion of elastin, and over time loses its elasticity, causing buckling and encroachment of the thecal sac. Further Reading: Baaj, Mummaneni, Uribe, Vaccaro, Greenberg. Handbook of Spine Surgery, 2016, lumbar laminectomy

Question 145

What is the smallest pedicle in the spine in most patients?
A. T1
B. T4
C. T7
D. L1

Answer 145

A. T1
B. T4
C. T7
D. L1

On average, T4 has the narrowest pedicle diameter and the shortest pedicle length Further Reading: Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatomy

Question 146

The annulus fibrosus is composed primarily of which type of collagen fibers?
A. Type I
B. Type II
C. Type III
D. Type IV

Answer 146

A. Type I
B. Type II
C. Type III
D. Type IV

The annulus fibrosus is comprised of obliquely oriented type I collagen fibers. The nucleus pulposus is primarily comprised of type II collagen. Further Reading: Kraemer. Intervertebral Disk Diseases, 3rd Edition, 2009, general anatomy, physiology, and biomechanics.

Question 147

You are performing a minimally invasive lumbar discectomy for a herniated disk in a 55-year-old man with radiculopathy. An intraoperative picture is shown. What structure is being elevated by the blunt nerve hook?
A. Lamina
B. Ligamentum flavum
C. Dura
D. Interspinous ligament
E. Disc fragment

Answer 147

A. Lamina
B. Ligamentum flavum
C. Dura
D. Interspinous ligament
E. Disc fragment

his image is a tubular discectomy and the blunt hook is elevating the yellow ligament, or ligamentum flavum, under which the dura can be seen. Further Reading: Fessler, Sekhar. Atlas of Neurosurgical Techniques: Spine and Peripheral Nerves, 2nd edition, 2016, figure 99.3, MIS posterior lumbar decompression of stenosis.

Question 148

The vertebral artery enters the foramen transversarium at what cervical level
A. C4
B. C5
C. C6
D. C7
E. T1

Answer 148

A. C4
B. C5
C. C6
D. C7
E. T1

The vertebral artery enters the foramen transversarium at C6 in most patients. In some, with aberrant vertebral anatomy, it can enter at C5. Further Reading: Spetzler, Kalani, Nakaji. Neurovascular Surgery, 2nd edition, 2015, microsurgical anatomy of the internal carotid and verteb

Question 149

The carotid tubercle is located on which cervical vertebral body?
A. C4
B. C5
C. C6
D. C7
E. T1

Answer 149

C. C6

The anterior tubercle of the sixth cervical vertebra is known as the carotid tubercle or Chassaignac tubercle. This separates the carotid artery from the vertebral artery and the carotid artery can be massaged against this tubercle to relieve the symptoms of supraventricular tachycardia. Further Reading: An, Singh. Synopsis of Spine Surgery, 2016, anatomy and surgical appro

Question 150

Which structure of the spine is demonstrated (arrow) in this intraoperative image leading into the abnormal mass?
A. Dentate ligament
B. Nerve root
C. Artery of Adamkiewicz
D. Filum terminale

Answer 150

A. C4
B. C5
C. C6
D. C7
E. T1

The filum terminale is a fibrous band extending inferiorly from the conus medullaris. It is often seen to have serpiginous vessels running along its course. It is often seen running through myxopapillary ependymomas. It is pictured in the intraoperative image above. Further Reading: Fessler, Sekhar. Atlas of Neurosurgical Techniques: Spine and Peripheral Nerves, 2nd edition, 2016, resection of cauda equina

Question 151

Which structure of the spine is depicted by number 2 in this axial
MRI?
A. Dentate ligament
B. Nerve root
C. Artery of Adamkiewicz
D. Filum terminale

Answer 151

A. Dentate ligament
B. Nerve root
C. Artery of Adamkiewicz
D. Filum terminale

The dentate ligaments of the spine extend laterally in between the dorsal and ventral nerve roots. It is an extension of the pia mater which extends to the arachnoid and dura laterally. It provides stability to the spinal cord within the spinal canal. Further Reading: Bambakidis, Dickman, Spetzler, Sonntag. Surgery of the Craniovertebral Junction, 2nd edition, 2013, anatomical basis of surgical approaches to the region of the foramen magnu

Question 152

Which structure of the spine is depicted by the arrow in this axial image?
A. Cruciate ligament
B. Apical ligament
C. Alar ligament
D. Transverse ligament

Answer 152

A. Cruciate ligament
B. Apical ligament
C. Alar ligament
D. Transverse ligament

The ligament depicted is the transverse ligament of the atlas. It is very important to assist with atlantoaxial stability. If there is a significant increase in atlantodental interval (> 3 mm), there is a high chance of transverse ligament injury and subsequent atlantoaxial instability. Further Reading: Bambakidis, Dickman, Spetzler, Sonntag. Surgery of the Craniovertebral Junction, 2nd edition, 2013, radiological evaluation of the craniovertebral junction.

Question 153

How far lateral from midline on the superior C1 posterior arch is the vertebral artery?
A. 0.5 cm
B. 1.0 cm
C. 1.5 cm
D. 2.0 cm

Answer 153

A. 0.5 cm
B. 1.0 cm
C. 1.5 cm
D. 2.0 cm

On average, the vertebral artery is 14.6 mm from midline on the superior aspect of the C1 posterior arch Further Reading: Cacciola et al. Vertebral artery in relationship to C1-C2 vertebrae: An anatomical study. 2004. Citow, Macdonald, Refai. Comprehensive Neurosurgery Board Review, 2nd edition, 2010, anatomy

Question 154

Which structure is fractured on these images?
A. Pars interarticularis
B. Pedicle
C. Spinous process
D. Superior articulating process

Answer 154

A. Pars interarticularis
B. Pedicle
C. Spinous process
D. Superior articulating process

This CT scan depicts a defect of the pars interarticularis, a major structure of the posterior spinal elements that provides stability within a spinal level. The pars interarticularis is the region of bone between the superior articulating process/pedicle and inferior articulating process. It is a good marker for the location of the exiting nerve root. During a laminectomy, care should be taken not to take the bone work too laterally as iatrogenic violation of the pars can lead to instability. Further Reading: Fessler, Sekhar. Atlas of Neurosurgical Techniques: Spine and Peripheral Nerves, 2nd edition, 2016, spondylolysis and spondylolisthesis in childre

Question 155

Which structure is demonstrated by number 11 on the corresponding images?
A. Zygapophyseal joint
B. Uncinate process
C. Facet joint
D. Costovertebral joint

Answer 155

A. Zygapophyseal joint
B. Uncinate process
C. Facet joint
D. Costovertebral joint

The uncovertebral joints are located laterally on each cervical vertebral body. They are formed by the uncinate processes and they help to provide stability to the cervical spine by limiting lateral movement. Further Reading: Forsting, Jansen. MR Neuroimaging: Brain, Spine, Peripheral Nerves, 2017, anato

Question 156

Which vertebral body is depicted in this image?
A. Atlas
B. Axis
C. C3
D. C4

Answer 156

A. Atlas
B. Axis
C. C3
D. C4

The vertebral body depicted here is the axis, or C2. It is the underside of the C2 body. Hints that this is C2 and not C1 include the presence of a formed vertebral body, as well as a spinous process. Further Reading: Goel, Cacciola. The Craniovertebral Junction: Diagnosis, Pathology, Surgical Techniques, 2011, image-guided surgery in the craniovertebral junction and upper cervical spine.

Question 157

Each segment of the brachial plexus gives rise to a branch that innervates the upper extremity except?
A. Roots
B. Trunks
C. Divisions
D. Cords

Answer 157

A. Roots
B. Trunks
C. Divisions
D. Cords

Each segment of the brachial plexus (roots, trunks, divisions, cords, branches) gives off a branch that innervates the upper extremity except the divisions, which do not have any individual branches. Further Reading: Psaaros. The Definitive Neurosurgical Board Review, page 60 Mackinnon, Yee. Nerve Surgery, 2015, brachial plexus injuries

Question 158

The lateral root of the median nerve (from the lateral cord) innervates what upper extremity functions
A. Hand intrinsics
B. Wrist extensors
C. Wrist flexors
D. Hand sensation

Answer 158

D. Hand sensation

The lateral cord is formed by the anterior divisions from the upper and middle trunks. The lateral cord divides into the musculocutaneous nerve and the lateral root of the median nerve. It is often described that the lateral cord contributions to the median nerve contain mostly sensory fibers traveling to the hand, while the medial cord contributions to the median nerve contain motor nerves controlling intrinsic hand function. Further Reading: Psaaros. The Definitive Neurosurgical Board Review, page 60. Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy

Question 159

What is the first branch off of the brachial plexus?
A. Long thoracic nerve
B. Dorsal scapular nerve
C. Nerve to the subclavius
D. Suprascapular nerve

Answer 159

A. Long thoracic nerve
B. Dorsal scapular nerve
C. Nerve to the subclavius
D. Suprascapular nerve

The first branch off the brachial plexus is the dorsal scapular nerve, branching off the C5 nerve root, which supplies the rhomboids and the levator scapulae. Next, the long thoracic nerve branches to innervate the serratus anterior. Diminished function in these muscles can represent a clinical confirmation of proximal root injury to the plexus. Further Reading: Psaaros. The definitive neurosurgical board review, page 60. Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy.

Question 160

You are evaluating a patient who had an upper respiratory tract illness 1 week ago. Two days after his symptoms resolved, he had the onset of severe right shoulder pain followed 24 hours later by weakness of shoulder abduction for the first 15 degrees and some weakness of external rotation. Which nerve is affected?
A. Axillary nerve
B. Musculocutaneous nerve
C. Dorsal scapular nerve
D. Suprascapular nerve

Answer 160

A. Axillary nerve
B. Musculocutaneous nerve
C. Dorsal scapular nerve
D. Suprascapular nerve

The suprascapular nerve branches off the upper trunk and innervates the supraspinatous and infraspinatous muscles, responsible for initial shoulder abduction and external rotation. The patient likely has idiopathic brachial plexitis, or Parsonage-Turner syndrome. Further Reading: Psaaros. The definitive neurosurgical board review, page 60. Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy

Question 161

The musculocutaneous nerve innervates all of these muscles except?
A. Coracobrachialis
B. Biceps brachii
C. Brachioradialis
D. Brachialis

Answer 161

A. Coracobrachialis
B. Biceps brachii
C. Brachioradialis
D. Brachialis

Innervation from the musculocutaneous nerve can be remembered as “BBC” Biceps, brachialis, and coracobrachialis. The brachioradialis is innervated by C6 through the radial nerve. The musculocutaneous nerve also gives a sensory branch to the lateral forearm via the lateral antebrachial cutaneous nerve. Further Reading: Psaaros. The definitive neurosurgical board review, page 60. Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy

Question 162

Which is the most distal branch of the medial cord listed here?
A. Anterior division
B. Medial pectoral nerve
C. Medial brachial cutaneous nerve
D. Medial antebrachial cutaneous nerve

Answer 162

A. Anterior division
B. Medial pectoral nerve
C. Medial brachial cutaneous nerve
D. Medial antebrachial cutaneous nerve

The medial cord has 5 total branches, the medial pectoral nerve (supplying the pectoralis minor and some of the pectoralis major), the medial brachial cutaneous nerve (sensory information from medial upper arm), the medial antebrachial cutaneous nerve (sensory information from medial forearm), and the final two branches, the ulnar nerve and medial contribution to the median nerve. In the options listed above, the medial antebrachial cutaneous nerve (MABC) is the most distal along the medial cord. Further Reading: Psaaros. The Definitive Neurosurgical Board Review, page 60. Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy.

Question 163

You are evaluating a patient who clearly has dysfunction of her latissimus dorsi. Which segment of the brachial plexus does its innervating nerve branch from?
A. Lateral cord
B. Posterior cord
C. Medial cord
D. Ventral roots

Answer 163

A. Lateral cord
B. Posterior cord
C. Medial cord
D. Ventral roots

The thoracodorsal nerve supplies the latissimus dorsi, and it branches as one of the five branches from the posterior cord (upper subscapular nerve, thoracodorsal nerve, lower subscapular nerve, axillary nerve, radial nerve). Further Reading: Psaaros. The Definitive Neurosurgical Board Review, page 61. Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy.

Question 164

Which muscle listed below does the axillary nerve innervate?
A. Teres minor
B. Teres major
C. Infraspinatous
D. Supraspinatous

Answer 164

A. Teres minor
B. Teres major
C. Infraspinatous
D. Supraspinatous

The axillary nerve branches from the posterior cord and mainly supplies the deltoid muscle. It also innervates the teres minor as well as a patch of skin overlying the shoulder Further Reading: Psaaros. The Definitive Neurosurgical Board Review, page 61. Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy.

Question 165

What is the pure motor branch of the radial nerve in the forearm?
A. Anterior interosseous nerve
B. Posterior interosseous nerve
C. Superficial branch
D. Dorsal digital branch

Answer 165

A. Anterior interosseous nerve
B. Posterior interosseous nerve
C. Superficial branch
D. Dorsal digital branch

The posterior interosseous nerve is a pure motor branch of the radial nerve in the forearm. It innervates the abductor pollicis longus, the extensor pollicis longus/brevis, extensor indices, extensor carpi ulnaris, extensor digitorum and extensor digit minimi. Further Reading: Psaaros. The definitive neurosurgical board review, page 61. Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy.

Question 166

What is the pure motor branch of the median nerve in the forearm?
A. Anterior interosseous nerve
B. Posterior interosseous nerve
C. Superficial branch
D. Dorsal digital branch

Answer 166

A. Anterior interosseous nerve
B. Posterior interosseous nerve
C. Superficial branch
D. Dorsal digital branch

Question 167

You are evaluating a patient with cramping of the hand that is better when he shakes the hand, thenar atrophy, and sensory disturbances in the first three digits and the lateral aspect of the 4th. Which structure is causing the nerve compression?
A. Volar carpal ligament
B. Transverse carpal ligament
C. Ligament of Struthers
D. Arcade of Frohse

Answer 167

A. Volar carpal ligament
B. Transverse carpal ligament
C. Ligament of Struthers
D. Arcade of Frohse

The patient is experiencing symptoms of carpal tunnel syndrome, where compression of the distal median nerve by the transverse carpal ligament causes the classic syndrome. Symptoms are worsened by the Phalen test (flexion of the wrist for extended periods of time), and there may be a positive Tinel’s sign over the carpal tunnel. Further Reading: Psaaros. The Definitive Neurosurgical Board Review, page 61. Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, median nerve

Question 168

You are evaluating a patient with cramping of the hand that is better when he shakes the hand, hypothenar atrophy, and sensory disturbances in the medial aspect of the distal 4th digit and all of the distal 5th digit. What structure is causing the nerve compression?
A. Volar carpal ligament
B. Transverse carpal ligament
C. Ligament of Struthers
D. Arcade of Frohse

Answer 168

A. Volar carpal ligament
B. Transverse carpal ligament
C. Ligament of Struthers
D. Arcade of Frohse

The patient is experiencing symptoms of ulnar tunnel syndrome, where compression of the distal ulnar nerve by the volar carpal ligament within Guyon’s canal. Note that the dorsal ulnar cutaneous nerve, which provides sensory innervation to the dorsum of the ulnar aspect of the hand branches approximately 6cm proximal to Guyon’s canal, so if sensory disturbance is present here, look more medially for compression, such as in the cubital tunnel. Further Reading: Psaaros. The Definitive Neurosurgical Board Review, page 61. Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, ulnar nerve.

Question 169

This image demonstrates examination for scapular winging. Which nerve is the examiner testing for injury?
A. Dorsal scapular nerve
B. Long thoracic nerve
C. Thoracodorsal nerve
D. Lateral pectoral nerve

Answer 169

A. Dorsal scapular nerve
B. Long thoracic nerve
C. Thoracodorsal nerve
D. Lateral pectoral nerve

The correct answer is the long thoracic nerve, which innervates the serratus anterior. Winged scapulae on exam suggests injury to this nerve, and can be an important exam finding that suggests proximal brachial plexus injury. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy

Question 170

The following image demonstrates sensory innervation from what nerve?
A. Ulnar nerve
B. Median nerve
C. Radial nerve
**

Answer 170

A. Ulnar nerve
B. Median nerve
C. Radial nerve
D. Musculocutaneous nerve

This sensory territory is that of the lateral antebrachial cutaneous nerve, a branch off the musculocutaneous nerve. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy

Question 171

In this image the examiner is having the patient adduct the arm with the elbow fixed at 90 degrees. The muscle being tested here is innervated by what nerve from the brachial plexus?
A. Lateral pectoral nerve
B. Thoracodorsal nerve
C. Long thoracic nerve
D. Medial brachial cutaneous nerve

Answer 171

A. Lateral pectoral nerve
B. Thoracodorsal nerve
C. Long thoracic nerve
D. Medial brachial cutaneous nerve

This test evaluates the strength of the latissimus dorsi, which is innervated by the thoracodorsal nerve, a branch from the posterior cord. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy

Question 172

The following image demonstrates an examiner testing a muscle that is innervated by which nerve?
A. Dorsal scapular nerve
B. Medial antebrachial cutaneous nerve
C. Upper subscapular nerve
D. Lower subscapular nerve

Answer 172

A. Dorsal scapular nerve
B. Medial antebrachial cutaneous nerve
C. Upper subscapular nerve
D. Lower subscapular nerve

Question 173

In this image, the examiner is providing resistance while the patient is attempting to abduct the arm from the side. Which nerve is being tested here?
A. Dorsal scapular nerve
B. Nerve to subclavius
C. Suprascapular nerve
D. Lateral pectoral nerve

Answer 173

A. Dorsal scapular nerve
B. Nerve to subclavius
C. Suprascapular nerve
D. Lateral pectoral nerve

This test examines the supraspinatous muscle, which is innervated by the suprascapular nerve. This muscle abducts the arm for the first 15 degrees from a straight hanging position. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy

Question 174

In this image the examiner is resisting external rotation of the arm at 90 degrees flexion. What nerve innervates the muscle that performs this action?
A. Dorsal scapular nerve
B. Nerve to subclavius
C. Suprascapular nerve
D. Lateral pectoral nerve

Answer 174

A. Dorsal scapular nerve
B. Nerve to subclavius
C. Suprascapular nerve
D. Lateral pectoral nerve

This test examines the strength of the infraspinatous muscle, which primarily externally rotates the arm. It is innervated by the suprascapular nerve. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy

Question 175

Which nerve is depicted in this image?
A. Musculocutaneous nerve
B. Radial nerve
C. Median nerve
D. Ulnar nerve

Answer 175

A. Musculocutaneous nerve
B. Radial nerve
C. Median nerve
D. Ulnar nerve

This image depicts the quadrangular space on the back of the arm. The nerve that passes through this space is the axillary nerve as it travels to innervate the deltoid muscle. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, brachial plexus anatomy

Question 176

Which nerve provides the sensory innervation depicted in the following image?
A. Musculocutaneous nerve
B. Radial nerve
C. Median nerve
D. Ulnar nerve

Answer 176

A. Musculocutaneous nerve
B. Radial nerve
C. Median nerve
D. Ulnar nerve

This sensory innervation of the hand is provided by the median nerve. You can see the common digital branches as well as the palmar cutaneous branch, which branches prior to the carpal tunnel. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, median nerve

Question 177

You are evaluating a patient who clearly has dysfunction of the gluteus maximus. Which nerve innervates the gluteus maximus?
A. Superficial gluteal
B. Superior gluteal
C. Inferior gluteal
D. Obturator

Answer 177

A. Superficial gluteal
B. Superior gluteal
C. Inferior gluteal
D. Obturator

The gluteus maximus is innervated by the inferior gluteal nerve. The superior gluteal nerve innervates the gluteus minimus/medius and the tensor fascia lata. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, lumbosacral plexus

Question 178

You are performing a L4-5 fusion with a TLIF for spinal stenosis with spondylolisthesis on a 65-year-old man. To enhance your fusion rate, you decide to take autologous bone from the patient’s iliac crest. If you inadvertently damage the nerve at risk during iliac crest bone graft harvest, what deficit will the patient have postoperatively?
A. Sensory loss over the anterior thigh/groin
B. Sensory loss over the buttocks
C. Gluteus maximus
D. Gluteus minimus/medius

Answer 178

A. Sensory loss over the anterior thigh/groin
B. Sensory loss over the buttocks
C. Gluteus maximus
D. Gluteus minimus/medius

The superior cluneal nerve traverses the iliac crest to provide sensory innervation to the sacral area and superior two-thirds of the buttocks. It is at risk during iliac crest bone harvest. Further Reading: Psaaros. The definitive neurosurgical board review, page 62. Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, lumbosacral plexus

Question 179

You are evaluating an overweight police officer who has started to note the onset of patchy sensory loss and pain over the anterolateral right thigh. What nerve is affected in this classic condition?
A. Ilioinguinal nerve
B. Lateral femoral cutaneous nerve
C. Iliohypogastric nerve
D. Genitofemoral nerve

Answer 179

A. Ilioinguinal nerve
B. Lateral femoral cutaneous nerve
C. Iliohypogastric nerve
D. Genitofemoral nerve

This overweight police officer (wears a tight fitting belt all day), likely has meralgia parasthetica, a compressive condition affecting the lateral femoral cutaneous nerve. It classically presents in overweight patients as patchy sensory loss/pain over the anterolateral thigh. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, lumbosacral plexus. Psaaros. The definitive neurosurgical board review, page 62.

Question 180

The common peroneal component is located where in relation to the tibial component of the sciatic nerve?
A. Anterior
B. Posterior
C. Medial
D. Lateral

Answer 180

A. Anterior
B. Posterior
C. Medial
D. Lateral

The sciatic nerve is the largest nerve in the body and it has both tibial and common peroneal components. The lateral aspect of the sciatic nerve contains the common peroneal portion of the sciatic nerve. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, sciatic nerve.

Question 181

Which nerve has contributions from both the tibial and common peroneal nerve?
A. Sural nerve
B. Saphenous nerve
C. Superficial peroneal nerve
D. Deep peroneal nerve

Answer 181

A. Sural nerve
B. Saphenous nerve
C. Superficial peroneal nerve
D. Deep peroneal nerve

The sural nerve receives contributions from both the tibial and common peroneal nerves. It supplies sensory innervation to the lateral aspect of the lower leg and ankle. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, sciatic nerve.

Question 182

The tibialis anterior is innervated by which nerve?
A. Superficial peroneal nerve
B. Deep peroneal nerve
C. Tibial nerve
D. Sural nerve

Answer 182

A. Superficial peroneal nerve
B. Deep peroneal nerve
C. Tibial nerve
D. Sural nerve

The tibialis anterior is innervated by the deep branch of the common peroneal nerve. The superficial peroneal nerve innervates the muscles involved in foot eversion, the peroneus longus and brevis. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, sciatic nerve.

Question 183

You are evaluating a patient in the emergency department who is having urinary incontinence after a massive central disc herniation. The motor neurons that are damaged causing urinary incontinence are located where?
A. Interomediolateral nucleus
B. Marginal nucleus
C. Substantia gelatinosa
D. Onuf’s nucleus

Answer 183

A. Interomediolateral nucleus
B. Marginal nucleus
C. Substantia gelatinosa
D. Onuf’s nucleus

Onuf’s nucleus is located within the conus medullaris and it is a grouping of motor neurons that send projections through the pudendal nerve, controlling urinary and fecal continence. Further Reading: Alberstone, Benzel, Najm, Steinmetz. Anatomic Basis of Neurologic Diagnosis, 2009, spinal cord.

Question 184

Injury to the superficial branch of the common peroneal nerve would lead to what deficit on exam?
A. Impaired foot eversion
B. Impaired foot inversion
C. Impaired foot dorsiflexion
D. Impaired foot plantarflexion

Answer 184

A. Impaired foot eversion
B. Impaired foot inversion
C. Impaired foot dorsiflexion
D. Impaired foot plantarflexion

The superficial branch of the common peroneal nerve innervates the peroneus longus and brevis and controls foot eversion. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, sciatic nerve.

Question 185

Which structure is not located in the tarsal tunnel?
A. Tibial nerve
B. Flexor hallicus longus tendon
C. Tibialis posterior tendon
D. Flexor digitorum brevis tendon

Answer 185

A. Tibial nerve
B. Flexor hallicus longus tendon
C. Tibialis posterior tendon
D. Flexor digitorum brevis tendon

The tarsal tunnel contains the tibial nerve, posterior tibial artery, posterior tibial vein, flexor hallicus longus tendon, flexor digitorum longus tendon and the tibialis posterior tendon. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, sciatic nerve.

Question 186

You are seeing a patient with concerns for an L5 disc herniation. On exam, you note that she has weakness of her right extensor hallicus longus. What peripheral nerve innervates the EHL?
A. Superficial peroneal nerve
B. Deep peroneal nerve
C. Tibial nerve
D. Sural nerve

Answer 186

A. Superficial peroneal nerve
B. Deep peroneal nerve
C. Tibial nerve
D. Sural nerve

The extensor hallicus longus is innervated by the deep branch of the common peroneal nerve. Remember that the superficial branch, while providing sensory information to the majority of the dorsum of the foot, only innervates muscles involved in foot eversion (peroneus longus/brevis). The deep branch innervates the remaining foot extensors. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, sciatic nerve

Question 187

Which muscle extends the hip with some assistance of the hamstrings?
A. Gluteus minimus/medius and tensor fascia lata
B. Gluteus maximus
C. Gracilis
D. Adductor magnus

Answer 187

A. Gluteus minimus/medius and tensor fascia lata
B. Gluteus maximus
C. Gracilis
D. Adductor magnus

The gluteus maximus muscle is innervated by the inferior gluteal nerve, and it extends the hip with the assistance of the hamstrings. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, lumbosacral plexus

Question 188

Fibers from Onuf’s nucleus are carried through which nerve?
A. Pudendal nerve
B. Superior gluteal nerve
C. Inferior gluteal nerve
D. Obturator nerve

Answer 188

A. Pudendal nerve
B. Superior gluteal nerve
C. Inferior gluteal nerve
D. Obturator nerve

Onuf’s nucleus is located within the conus medullaris and contains motor neurons that control urinary and fecal continence. Fibers are carried through the pudendal nerve. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, inguinal complex of nerves.

Question 189

Fibers ultimately destined for the peroneus longus travel through which nerve?
A. Femoral nerve
B. Obturator nerve
C. Sciatic nerve
D. Tibial nerve

Answer 189

A. Femoral nerve
B. Obturator nerve
C. Sciatic nerve
D. Tibial nerve

Fibers that innervate the peroneus longus originate in the peroneal component of the sciatic nerve. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, sciatic nerve.

Question 190

Fibers ultimately destined for the flexor hallicus longus travel through which nerve?
A. Femoral nerve
B. Obturator nerve
C. Sciatic nerve
D. Peroneal nerve

Answer 190

A. Femoral nerve
B. Obturator nerve
C. Sciatic nerve
D. Peroneal nerve

The flexor hallicus is innervated by the tibial nerve. Fibers innervating the flexor hallicus longus travel within the sciatic nerve before separating to become the tibial nerve. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, sciatic nerve.

Question 191

Which nerve provides the sensory innervation depicted in the following image?
A. Sural nerve
B. Sciatic nerve
C. Tibial nerve
D. Saphenous nerve

Answer 191

A. Sural nerve
B. Sciatic nerve
C. Tibial nerve
D. Saphenous nerve

This image depicts the sensory innervation of the sural nerve. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, sciatic nerve.

Question 192

You are evaluating a patient with sensory loss on the anterolateral aspect of the thigh. Which nerve innervates the anterolateral thigh?
A. Ilioinguinal nerve
B. Genitofemoral nerve
C. Lateral femoral cutaneous nerve
D. Obturator nerve

Answer 192

A. Ilioinguinal nerve
B. Genitofemoral nerve
C. Lateral femoral cutaneous nerve
D. Obturator nerve

Sensory innervation from the anterolateral thigh is provided by the lateral femoral cutaneous nerve. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, inguinal complex of nerves.

Question 193

Which nerve is being evaluated by the examiner in this image?
A. Obturator nerve
B. Sciatic nerve
C. Femoral nerve
D. Ilioinguinal nerve

Answer 193

A. Obturator nerve
B. Sciatic nerve
C. Femoral nerve
D. Ilioinguinal nerve

This examiner is evaluating the strength of the quadriceps muscle, which is innervated by the femoral nerve. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, inguinal complex of nerves

Question 194

Which nerve controls adduction of the thigh?
A. Obturator nerve
B. Sciatic nerve
C. Femoral nerve
D. Ilioinguinal nerve

Answer 194

A. Obturator nerve
B. Sciatic nerve
C. Femoral nerve
D. Ilioinguinal nerve

The obturator nerve innervates the adductors longus, brevis and magnus. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, inguinal complex of nerves.

Question 195

You are evaluating a 53-year-old woman who presents with sensory loss in the upper anterior thigh region as well as part of her labia. Where does this nerve pass in relation to the inguinal ligament?
A. Above
B. Below
C. Both
D. Neither

Answer 195

A. Above
B. Below
C. Both
D. Neither

This sensory innervation is from the genitofemoral nerve which supplies two regions as depicted in the image above. The femoral triangle region is innervated by the nerve branch that passes below the inguinal ligament, while the groin region is innervated by the branch that passes through the spermatic cord. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, inguinal complex of nerves.

Question 196

Depicted here is the lumbar plexus. The lumbosacral trunk connects to which structure?
A. Sciatic nerve
B. Sacral plexus
C. Psoas muscle
D. Rectus fascia

Answer 196

A. Sciatic nerve
B. Sacral plexus
C. Psoas muscle
D. Rectus fascia

The lumbosacral trunk provides the connection between the lumbar plexus and the sacral plexus. It travels on the psoas muscle. It contributes to multiple sacral plexus nerves, including the superior and inferior gluteal nerves. Further Reading: Russell. Examination of Peripheral Nerve Injuries: An Anatomical Approach, 2015, inguinal complex of nerves.