Anatomy

Question 1

A lesion in the pulvinar nucleus of the thalamus can result in:
A. Neglect syndromes
B. Anosmia
C. Contralateral sensory loss
D. Endocrine dysfunction and abnormalities
E. Memory difficulties

Answer 1

A. Neglect syndromes

Neglect syndromes and attentional deficits can
occur with pulvinar nuclear lesions. The pulvinar
nucleus is the largest nucleus in the thalamus; it
is located most posteriorly, and is associated with
visual
pathways. (E) Memory difficulties may occur
with lesions of the anterior nucleus of the thalamus,
which is considered part of the limbic system.

Question 2

A 67-year-old woman presents for follow-up 4 months after a stroke. She complains of her eyelids “twitching.” She is found to have palatal myoclonus on physical exam. Her stroke likely involved what region of the brain?
A. Nucleus ambiguus
B. Tectospinal tract
C. Rubro-olivary tract/central tegmental tract (triangle of Mollaret)
D. Body of the caudate nucleus
E. Lateral lemniscus

Answer 2

C. Rubro-olivary tract/central tegmental tract (triangle of Mollaret)

The triangle of Mollaret is a functional circuit
connecting the dentate nucleus of the cerebellum
to the contralateral red nucleus through the superior
cerebellar peduncle, the red nucleus to the ipsilateral
inferior olivary nucleus through the central
tegmental tract, the inferior olivary nucleus to the
contralateral cerebellar cortex through the inferior
cerebellar peduncle, and the cerebellar cortex to
the ipsilateral dentate nucleus. Lesions of the triangle
of Mollaret produce palatal myoclonus, which
is one of the few movement disorders that do not
disappear during sleep. Palatal myoclonus appears
in a delayed fashion following such lesions. Ocular
myoclonus can accompany palatal myoclonus due
to lesions in the central tegmental tract.

Question 3

The ventral tegmental area sends projections through what neuroanatomic structure to the nucleus accumbens as part of the dopaminergic mesolimbic system (involved in reward circuitry)?
A. Medial forebrain bundle
B. Lateral hypothalamus
C. Ventral pallidum
D. Prefrontal cortex

Answer 3

A. Medial forebrain bundle

The medial forebrain bundle carries information
from the ventral tegmental area to the nucleus
accumbens in the ventral striatum. The nucleus
accumbens also receives input from the hippocampus,
amygdala, and prefrontal cortex with output
to the ventral pallidum.

Question 4

What structure is the target for taste afferent fibers?
A. Area postrema
B. Nucleus tractus solitarius
C. Nucleus prepositus hypoglossi
D. Nucleus ambiguus
E. Inferior salivary nucleus

Answer 4

B. Nucleus tractus solitarius

The nucleus tractus solitarius is a medullary
nucleus
also receiving afferents from chemoreceptors
in the aortic and carotid bodies.

Question 5

What structure is the autonomic center for vomiting?
A. Area postrema
B. Nucleus tractus solitarius
C. Nucleus prepositus hypoglossi
D. Nucleus ambiguus
E. Inferior salivary nucleus

Answer 5

A. Area postrema

The area postrema is located in the medulla and
is the only paired circumventricular organ. (C) The
nucleus prepositus hypoglossi is a medullary structure
and neural integrator responsible for horizontal
gaze control during smooth-pursuit eye movements.
(D) The nucleus ambiguus is located in the lateral
and rostral medulla and supplies the efferent motor
fibers for the glossopharyngeal and vagus nerves.
(E) The inferior salivary nucleus is a medullary
structure responsible for the parasympathetic
efferents
to the parotid gland to induce salivation.

Question 6

What skin mechanoreceptors are best at sensing both rapid vibration and pressure?
A. Ruffini endings
B. Meissner corpuscles
C. Merkel disks
D. Pacinian corpuscles
E. Free nerve endings

Answer 6

D. Pacinian corpuscles

Pacinian corpuscles detect rapid vibrations and
have peak sensitivity with vibrations around 250
Hz. They also are keen at detecting surface texture,
which makes their localization in the skin ideal.
Additionally, they are found in internal organs.
(A) Ruffini endings are slowly adapting receptors
found in subcutaneous tissues and respond to sustained
pressure. (B) Meissner corpuscles are very
sensitive to light touch and function best with vibrations
less than 50 Hz. They rapidly adapt and
are found in areas very sensitive to light touch,
such as the finger pads. (C) Merkel disks occur in
the superficial skin layers and mucosa, and provide
information about pressure and texture. They are
slowly adapting. (E) Free nerve endings are unencapsulated
receptors in the skin that detect painful
stimuli.

Question 7

In what ventricular structure is cerebrospinal fluid not produced by the choroid plexus?
A. Roof of the fourth ventricle
B. Floor of the third ventricle
C. Lateral recess of the foramen of Luschka
D. Temporal horn of the lateral ventricle
E. Roof of the third ventricle

Answer 7

B. Floor of the third ventricle

There is no choroid plexus along the floor of the
third ventricle. Choroid plexus is present at the
other locations and is responsible for the bulk of
cerebrospinal fluid production. Cerebrospinal fluid
is produced by bulk transependymal flow along
the floor of the third ventricle.

Question 8

The deep petrosal nerve is what type of nerve with what function?
A. Sensory nerve that unites with the greater
superficial petrosal nerve to form the nerve
of the pterygoid canal
B. Sympathetic nerve that unites with the lesser
superficial petrosal nerve to form the vidian
nerve
C. Sympathetic nerve that unites with the greater superficial petrosal nerve to form the vidian nerve
D. Sensory nerve that unites with the lesser
superficial petrosal nerve to form the nerve
of the pterygoid canal

Answer 8

C. Sympathetic nerve that unites with the greater superficial petrosal nerve to form the vidian nerve

The deep petrosal nerve emerges from the internal
carotid plexus and traverses the carotid canal
to join the superficial petrosal nerve to form the
Vidian nerve (also known as the nerve of the pterygoid
canal). The deep petrosal nerve carries the
sympathetics that innervate the pterygopalatine
ganglion.

Question 9

What nerve innervates the skin between the hallux and the second toe?
A. Superficial peroneal nerve
B. Medial dorsal cutaneous nerve
C. Intermediate dorsal cutaneous nerve
D. Deep peroneal nerve
E. Tibial nerve

Answer 9

D. Deep peroneal nerve

The deep peroneal nerve innervates the tibialis
anterior, extensor digitorum longus, extensor hallucis
longus, extensor digitorum brevis, and extensor
hallucis brevis, and provides cutaneous innervation
to the webbing between the first and second
toes. (A) The superficial peroneal nerve innervates
the peroneus longus and brevis, and provides cutaneous
innervation over the anterolateral leg and the
dorsum of the foot, except for the first web space.
(B) The medial dorsal cutaneous nerve divides
into three branches, and provides sensation to the
medial
side of the hallux and adjacent sides of the
second and third toes. (C) The intermediate dorsal
cutaneous nerve divides into four branches, and
supplies sensation to the medial and lateral sides
of the third, fourth, and fifth toes. (E) The tibial
nerve innervates the gastrocnemius, popliteus,
soleus,
and plantaris, and contributes to the sural
nerve. It also innervates the tibialis posterior, flexor
digitorum longus, flexor hallucis longus, sole of the
foot, and posterior lower leg.

Question 10

What is another name for the medial distal striate artery?
A. Tentorial artery (of Bernasconi and Cassinari)
B. McConnell capsular artery
C. Frontopolar artery
D. Recurrent artery of Heubner
E. Medial lenticulostriate artery

Answer 10

D. Recurrent artery of Heubner

The recurrent artery of Heubner is the most
proximal branch of the A2 segment distal to the
anterior communicating artery. It runs in a retrograde
fashion and enters the anterior perforating
substance. (A) The tentorial artery is a branch of
the meningohypophyseal trunk that runs posteriorly
to supply blood to the tentorium. (B) The
McConnell
capsular artery/arteries arise from the
medial trunk of the intracavernous internal carotid
artery and supply blood to the pituitary
gland. They are present in only 28% of the population.
(C) The frontopolar artery is a branch of the
A2 segment that supplies blood to the medial frontal
lobe and the lateral surface of the superior frontal
gyrus. (E) The medial lenticulostriate arteries
arise from the A1 segment and supply blood to the
globus pallidus and medial putamen.

Question 11

What midbrain anatomic structure is responsible for pain modulation?
A. Superior colliculus
B. Substantia nigra
C. Crus cerebri
D. Red nucleus
E. Periaqueductal gray matter

Answer 11

E. Periaqueductal gray matter

The periaqueductal gray matter suppresses and
modulates pain in the descending pathways within
the midbrain tegmentum. (A) The superior colliculus
functions to modulate gaze shifts. (B) The substantia
nigra contains high levels of dopamine, and
the loss of neurons in the pars compacta region
characterizes Parkinson disease. (C) The crus cerebri
is the anterior white matter portion of the cerebral
peduncle that contains the motor tracts. (D) The
red nucleus controls tone and gait.

Question 12

A patient has an intractable nosebleed following transsphenoidal pituitary surgery. What artery likely is injured?
A. Middle meningeal artery
B. Infraorbital artery
C. Internal maxillary artery
D. Superior hypophyseal artery
E. Anterior ethmoidal artery

Answer 12

C. Internal maxillary artery

Epistaxis after transsphenoidal surgery can be
immediate
or delayed. Injury to the internal carotid
artery can cause life-threatening epistaxis, and
pseudoaneurysm formation can lead to delayed
hemorrhage, illustrating the need for an angiogram
after suspected injury. In the external carotid
system, the sphenopalatine artery, originating from
the internal maxillary artery, is the most common
branch injured during transsphenoidal surgeries.
The artery is found in the inferolateral corner of the
sphenoid ostium, and if it is injured, it can retract
toward the maxilla and be difficult to coagulate.

Question 13

A patient presents with a winged scapula. What other nerve besides the long thoracic and dorsal scapular nerves may be injured?
A. Suprascapular nerve
B. Spinal accessory nerve
C. Thoracodorsal nerve
D. Lateral thoracic nerve

Answer 13

B. Spinal accessory nerve

The long thoracic nerve provides innervation
to the serratus anterior and is the most common
cause of scapular winging. Its origin is the C5-C7
nerve roots. The dorsal scapular nerve (arising
from the C5 root) innervates the rhomboids and
levator scapulae. The spinal accessory nerve
innervates
the trapezius and sternocleidomastoid.
Injury to any of these three nerves can cause
a winged scapula. (A) The suprascapular nerve
innervates
the supraspinatus and infraspinatus.
It is a branch of the upper trunk of the brachial
plexus. (C) The thoracodorsal nerve emerges from
the posterior cord and innervates the latissimus
dorsi. (D) The lateral thoracic nerve does not exist.

Question 14

What leptomeningeal structure is composed only of a single layer?
A. Intracranial dura
B. Spinal dura
C. Pia mater
D. Arachnoid

Answer 14

B. Spinal dura

C is the location of the lateral component of the
spinothalamic tracts. (A) A is the location of the
dorsal columns. (B) B is the location of the anterior
portion of the corticospinal tracts. (D) D is the
location
of the lateral corticospinal tracts. (E) E is
the location of the reticulospinal tracts.

Question 14

In this spinal cord cross-sectional image, what letter corresponds to the location of the spinothalamic tract?
A. A
B. B
C. C
D. D
E. E

Answer 14

C. C

Question 15

The supplementary motor area is found at what location:
A. Along the midline surface of the cerebral
hemisphere just anterior to the primary motor**
cortex leg area
B. In the parietal operculum just rostral to the
lateral sulcus
C. Along the lateral surface of the cerebral hemi-
sphere just anterior to the primary motor
cortex arm area
D. Within the pars opercularis and pars triangu-
laris of the inferior frontal gyrus
E. Along the medial surface of the cerebral hemi-
sphere continuous with the postcentral gyrus
of the parietal lobe

Answer 15

A. Along the midline surface of the cerebral
hemisphere just anterior to the primary motor**
cortex leg area

Injury or irritation of the supplementary motor
area produces a paucity of volitional movements
along with a contralateral hemineglect and apraxias.
Typically these symptoms resolve in a week or
two when they are due to supplementary motor
area damage, whereas the symptoms tend to be
long standing when they are due to damage of the
motor cortex. (B) The secondary somatosensory
area is found in the parietal operculum. (C) The
premotor cortex is in Brodmann area 6 on the lateral
surface of the cerebral hemisphere. The medical
extension of this area is the supplementary
motor area. (D) The Broca area is within the pars
opercularis and pars triangularis of the inferior
frontal gyrus. (E) The paracentral lobule of the
parietal
lobule lies along the medial surface of
the cerebral hemisphere and is continuous with the
postcentral gyrus of the parietal lobe. The anterior
component of this (the medial surface of the precentral
gyrus) is the supplementary motor area.

Question 16

Which structure runs through the petrotympanic fissure?
A. Pterygoid artery
B. Posterior deep temporal artery
C. Chorda tympani
D. Lingual nerve
E. Greater superficial petrosal nerve

Answer 16

C. Chorda tympani

The petrotympanic fissure is located between the
temporomandibular joint and the middle ear to
enable communication between these structures.
It opens just anterior and superior to the tympanic
membrane, and houses the anterior malleus ligament,
anterior tympanic branch of the internal
maxillary artery, and chorda tympani. (A) The pterygoid
artery is a branch of the second part of the
internal maxillary artery and supplies blood to
the medial and lateral pterygoid muscles. (B) The
posterior deep temporal artery is a branch of the
second part of the internal maxillary artery and
supplies blood to the temporalis muscle. (D) The
chorda tympani does not join with the lingual
nerve until after it emerges from the skull through
the infratemporal fossa. (E) The greater superficial
petrosal nerve travels over the surface of the foramen
lacerum and joins the deep petrosal nerve to
form the nerve of the pterygoid canal (Vidian
nerve).

Question 17

Which bone does not contribute to both the orbit and nasal septum?
A. Frontal bone
B. Ethmoid bone
C. Maxillary bone
D. Palatine bone

Answer 17

A. Frontal bone

The orbit is made up of seven bones: pars orbitalis
of the frontal, lacrimal, lamina papyracea
of the ethmoid, zygomatic, maxillary, palatine, and
greater and lesser wings of the sphenoid. The nasal
septum is composed of five bones and structures:
perpendicular plate of the ethmoid, vomer, septum
cartilage, maxillary, and palatine.

Question 18

In the hand, what muscles are innervated by the median nerve?
A. Abductor pollicis brevis
B. Lumbricals 3 and 4
C. Adductor pollicis
D. Opponens digiti minimi
E. Abductor pollicis longus

Answer 18

A. Abductor pollicis brevis

The median nerve originates from the C5-T1
roots. In the hand, the median nerve innervates
the “LOAF” muscles (lumbricals 1 and 2, opponens
pollicis, abductor pollicis brevis, and flexor pollicis
brevis). The ulnar nerve innervates the opponens
digiti minimi, flexor digiti minimi brevis, abductor
digiti minimi, lumbricals 3 and 4, interossei, and
adductor pollicis. The radial nerve innervates the
extensors (digitorum, digiti minimi, carpi ulnaris,
pollicis brevis, pollicis longus, and pollicis indicis)
as well as the abductor pollicis longus.

Question 19

Embryologically, the pituitary is composed of the adenohypophysis and neurohypophysis. Rathke cleft cysts are derived from the persistence of what primary germ layer?
A. Ectoderm
B. Neuroectoderm
C. Mesoderm
D. Endoderm

Answer 19

A. Ectoderm

The pituitary is derived from the dual ectoderm.
Around day 28 of embryogenesis, the Rathke pouch
arises from a diverticulum from the stomodeum,
which is derived from the ectoderm. The infundibulum
arises from the neuroectoderm and grows
inferiorly, where it eventually contacts the Rathke
pouch. By the fifth week of embryogenesis, the
neck of the Rathke pouch contacts the infundibulum
and separates from the oral epithelium. The
residual lumen of the Rathke pouch narrows to
form a cleft and regresses. Persistence of the pouch
is considered to be the cause of a Rathke cleft cyst.

Question 20

The inferior aspect of the cuneus is bounded by what structure?
A. Tentorium
B. Parieto-occipital sulcus
C. Lingual gyrus
D. Collateral eminence
E. Calcarine sulcus

Answer 20

E. Calcarine sulcus

The cuneus (Brodmann area 17) is the primary
visual cortex and is bounded anteriorly by the
parieto-
occipital sulcus and inferiorly by the calcarine
sulcus. (C) The lingual gyrus lies between the
calcarine sulcus and posterior part of the collateral
sulcus and contributes to Brodmann area 19.
(D) The collateral eminence is found in the lateral
aspect of the occipital horn and is a result of invagination
of the collateral sulcus.

Question 21

From superior to inferior (rostral to caudal), what are the correct layers, in order, of the roof of the third ventricle?
A. Fornix, tela choroidea, velum interpositum, tela
choroidea, and choroid plexus
B. Choroid plexus, velum interpositum, tela cho-
roidea, and fornix
C. Fornix, velum interpositum, tela choroidea,
choroid plexus, and tela choroidea
D. Tela choroidea, fornix, tela choroidea, velum
interpositum, and choroid plexus
E. Fornix, velum interpositum, and choroid plexus

Answer 21

A. Fornix, tela choroidea, velum interpositum, tela
choroidea, and choroid plexus

The tela choroidea is composed of pia that sits on
the velum interpositum (the potential space containing
the internal cerebral veins). Failure of closure
of the posterior end of this potential space
results in a cavum velum interpositum that communicates
with the quadrigeminal cistern.

Question 22

What structure courses between the petrous temporal bone and basilar part of the occipital bone and drains blood from the cavernous sinus to the sigmoid sinus?
A. Superior petrosal sinus
B. Inferior petrosal sinus
C. Vein of Labbé
D. Basal vein of Rosenthal
E. Straight sinus

Answer 22

B. Inferior petrosal sinus

The inferior petrosal sinus drains into the sigmoid
sinus/jugular vein. (A) The superior petrosal
sinus runs along edge of the tentorium and drains
into the transverse sinus. (C) The vein of Labbé is a
superficial vein that anastomoses the middle cerebral
vein with the transverse sinus. (D) The basal
vein of Rosenthal begins in the anterior perforated
substance and receives contributions from the
anterior cerebral vein, deep sylvian vein, and inferior
striate veins. The basal vein of Rosenthal then
passes around the cerebral peduncle to drain blood
into the vein of Galen. (E) The straight sinus is the
union of the vein of Galen and inferior sagittal sinus
and drains into the torcular/transverse sinus.

Question 22

Which structure primarily is responsible for carrying input to the cerebellum from the contralateral cerebral cortex?
A. Inferior cerebellar peduncle
B. Middle cerebellar peduncle
C. Superior cerebellar peduncle
D. Cerebral peduncle

Answer 22

B. Middle cerebellar peduncle

Corticopontine fibers project through the middle
cerebellar peduncle (brachium pontis) along
pontocerebellar fibers. (A) The inferior cerebellar
peduncle (restiform and juxtarestiform bodies)
receives signals from the spinocerebellar tract, olivary
nucleus, and vestibular nuclei. (C) Most fibers
emerging from the cerebellum do so through the
superior cerebellar peduncle (brachium conjunctivum)
and then synapse on the red nucleus or
motor nuclei of the thalamus.

Question 23

What structure in the medial limbic circuit is the major output of the thalamus? A. Hippocampus B. Amygdala C. Fornix D. Entorhinal cortex E. Cingulate gyrus

Answer 23

E. Cingulate gyrus ## Footnote The medial limbic circuit also is known as the Papez circuit. It essentially is the limbic system circuitry. The Papez circuit begins in the hippocampus (subiculum) and then projects to the fornix followed by the mammillary bodies. The mammillary bodies project along the mammillothalamic tract to the anterior thalamic nucleus and then to the cingulum followed by the entorhinal cortex. The circuit is completed as the entorhinal cortex projects back to the hippocampus.

Question 24

What is an accurate description of the location of the flocculonodular lobe of the cerebellum? A. Rostral to the primary fissure B. Caudal to the primary fissure C. Anterior to and between the anterior and posterior cerebellar lobes D. Midsagittal E. Rostral to the anterior lobe and posterior to the sylvian aqueduct

Answer 24

C. Anterior to and between the anterior and posterior cerebellar lobes ## Footnote The flocculonodular lobe is part of the vestibulocerebellum and is involved with maintenance of posture. (A) The anterior lobe is rostral to the primary fissure. (B) The posterior lobe is caudal to the primary fissure. (D) The vermis is located in a midsagittal position. (E) The tectum of the midbrain is rostral to the anterior lobe and posterior to the sylvian aqueduct.

Question 25

Afferents to the subthalamic nucleus originate in what structure? A. Thalamus B. Red nucleus C. Globus pallidus D. Cerebellum E. Substantia innominata

Answer 25

C. Globus pallidus ## Footnote The globus pallidus sends afferents to the subthalamic nucleus, which also receives fewer afferents from the substantia nigra pars compacta and pedunculopontine nucleus.

Question 26

The lateral cord of the brachial plexus is formed from what structure(s)? A. Anterior divisions of the upper and middle trunks B. Nerve roots C5, C6, and C7 C. Posterior divisions of the superior, middle, and inferior trunks D. Anterior division of the inferior trunk E. Posterior division of the superior trunk

Answer 26

A. Anterior divisions of the upper and middle trunks ## Footnote The lateral cord is derived from the anterior divisions of the superior and middle trunks. (C) The posterior cord is formed from the posterior divisions of the superior, middle, and inferior trunks. (D) The medial cord is formed from the anterior division of the inferior trunk.

Question 27

The ventral posterior nucleus of the thalamus sends information to which Brodmann area(s)? A. Areas 1, 2, and 3 B. Area 4 C. Area 17 D. Areas 39 and 40 E. Area 44

Answer 27

A. Areas 1, 2, and 3 ## Footnote The ventral posterior nucleus is subdivided into the ventral posterior lateral nucleus and the ventral posterior medial nucleus, which receive afferent sensory information from the medial lemniscus/ spinothalamic tract and trigeminothalamic tract, respectively. These nuclei then send projections to the primary somatosensory cortex in the postcentral gyrus (Brodmann areas 1, 2, and 3). (B) Brodmann area 4 is the primary motor cortex in the precentral gyrus. (C) Brodmann area 17 is the primary visual cortex in the occipital lobe. (D) Brodmann areas 39 and 40 are the angular gyrus and supramarginal gyrus, respectively, and represent the Wernicke area. (E) Brodmann area 44 is the pars opercularis of the inferior frontal gyrus and represents the Broca area.

Question 28

The sural nerve provides sensation to the posterolateral surface of the leg, lateral foot, and the fifth toe. It is formed by contributions from which nerve(s)? A. Tibial nerve B. Common peroneal nerve C. Tibial and common peroneal nerves D. Superficial peroneal nerve E. Tibial and superficial peroneal nerves

Answer 28

C. Tibial and common peroneal nerves ## Footnote The sural nerve is composed of contributions from the medial cutaneous branch arising from the tibial nerve and the lateral cutaneous branch arising from the common peroneal nerve.

Question 29

If the facial nerve is sectioned just proximal to the nerve to the stapedius, what clinical finding would be expected other than paresis of the facial musculature? A. Decreased lacrimation B. Decreased taste in the anterior two thirds of the tongue C. Increased salivation D. Decreased sensation in the nasopharynx and palate mucous membranes

Answer 29

B. Decreased taste in the anterior two thirds of the tongue ## Footnote Facial nerve branches distal to the nerve to the stapedius include the chorda tympani, which serves to provide taste to the anterior two thirds of the tongue. (A) The greater petrosal nerve is the first branch of the facial nerve distal to the geniculate ganglion (proximal to the emergence of the nerve to the stapedius). The greater petrosal nerve innervates the lacrimal gland after sending fibers through the zygomatic nerve. (C) Decreased salivation would be expected as the facial nerve innervates the submandibular and sublingual glands through the chorda tympani. (D) The nervus intermedius provides the sensory and parasympathetic components for cranial nerve VII. It joins the motor root of the nerve at the geniculate ganglion and provides minor sensory innervation to the oropharynx and auricle.

Question 30

What muscle is innervated by the anterior interosseous nerve? A. Flexor pollicis brevis B. Abductor pollicis brevis C. Flexor carpi radialis D. Pronator quadratus E. Abductor pollicis longus

Answer 30

D. Pronator quadratus ## Footnote The anterior interosseous nerve is a branch of the median nerve and classically innervates two and a half muscles: the flexor pollicis longus, pronator quadratus, and radial half of flexor digitorum profundus. It contains no sensory fibers. (A–C) The median nerve proper innervates the flexor pollicis brevis, abductor pollicis brevis, and flexor carpi radialis. (E) The abductor pollicis longus is innervated by the posterior interosseous nerve from the radial nerve.

Question 31

Brodmann area 39 may be considered part of what cortical area? A. Broca area B. Visual cortex C. Somatosensory association cortex D. Wernicke area E. Auditory cortex

Answer 31

D. Wernicke area ## Footnote The Wernicke area often is localized to the angular gyrus on the banks of the superior temporal sulcus and the supramarginal gyrus found on the banks of the sylvian fissure (Brodmann areas 39 and 40, respectively). Some neuroanatomists also consider the posterior part of Brodmann area 22 (the superior temporal gyrus) to be a part of the Wernicke area. (A) The Broca area is Brodmann area 44 and consists of the pars opercularis of the inferior frontal gyrus and, included by some neuroanatomists, the pars triangularis (Brodmann area 45). (B) The primary visual cortex is Brodmann area 17, whereas Brodmann area 18 is the secondary visual cortex. (C) The somatosensory association cortex is Brodmann area 7. (E) Brodmann area 22 along with the more medially located Brodmann area 41 (the Heschl gyrus) are the primary auditory cortex.

Question 32

The inferior leaflet of the Liliequist membrane separates the interpeduncular from the prepontine cistern. The superior leaflet separates which two cisterns medially? A. Chiasmatic and crural cisterns B. Interpeduncular and crural cisterns C. Interpeduncular and chiasmatic cisterns D. Ambient and quadrigeminal cisterns E. Interpeduncular and ambient cisterns

Answer 32

C. Interpeduncular and chiasmatic cisterns ## Footnote The Liliequist membrane separates the interpeduncular from the chiasmatic cistern medially and the carotid cistern laterally. Blood in the chiasmatic cistern should raise concern for aneurysmal rupture.

Question 33

Innervation of the facet joints in the lumbar spine is provided by what nerve? A. Lateral branch of the dorsal ramus B. Ventral ramus C. Medial branch of the dorsal ramus D. Ramus communicans E. Dorsal root

Answer 33

C. Medial branch of the dorsal ramus ## Footnote The medial branch of the dorsal (posterior) ramus innervates the facet capsule, synovium, multifidus, ligaments, and periosteum of the vertebral arches. (A) The lateral branch of the dorsal ramus innervates the paraspinous musculature and proximal sensory dermatomes. (B) The ventral ramus innervates the musculature and dermatomes of the limbs and truck. The meningeal branch (the sinuvertebral nerve) arises from the spinal nerve root and reenters the intervertebral foramen. (D) The ramus communicans contains autonomic nerves. (E) The dorsal/posterior root contains the afferent (sensory) nerves that contribute to the spinal nerve.

Question 34

Which of the following is true regarding the cerebellothalamic tract (dentatothalamic tract)? A. It is an uncrossed tract arising from the den- tate nucleus that passes through the superior cerebellar peduncle and terminates in the ven- tral anterior nucleus of the thalamus. B. It is an uncrossed tract arising from the den- tate nucleus that passes through the middle cerebellar peduncle and terminates in the ven- tral anterior nucleus of the thalamus. C. It is a crossed tract arising from the dentate nucleus that passes through the superior cere- bellar peduncle and terminates in the ventral anterior nucleus of the thalamus D. It is a crossed tract arising from the dentate nucleus that passes through the middle cere- bellar peduncle and terminates in the ventral anterior nucleus of the thalamus. E. It is an uncrossed tract arising from the den- tate nucleus that passes through the inferior cerebellar peduncle and terminates in the ven- tral anterior nucleus of the thalamus.

Answer 34

C. It is a crossed tract arising from the dentate nucleus that passes through the superior cere- bellar peduncle and terminates in the ventral anterior nucleus of the thalamus ## Footnote C It is a crossed tract arising from the dentate nucleus that passes through the superior cerebellar peduncle and terminates in the ventral anterior nucleus of the thalamus.

Question 35

Pain and temperature fibers from the face are relayed to what nucleus? A. Mesencephalic nucleus of cranial nerve V B. Ventral posterior lateral nucleus of the thalamus C. Principal sensory nucleus of cranial nerve V D. Solitary nucleus E. Spinal nucleus of cranial nerve V

Answer 35

E. Spinal nucleus of cranial nerve V ## Footnote Pain and temperature signals from the face travel through the spinal tract of cranial nerve V to terminate in the spinal nucleus of cranial nerve V, which extends into the cervical spinal cord. (A) Proprioceptive fibers travel to the mesencephalic nucleus of cranial nerve V. (B) Sensory fibers travel to the ventral posterior medial nucleus of the thalamus. (C) Pressure and vibration signals terminate in the chief (principal) nucleus of cranial nerve V. (D) The solitary nucleus receives gustatory signals and regulates cardiorespiratory and gastrointestinal processes.

Question 36

What is the most proximal artery originating from the carotid artery distal to the ophthalmic artery? A. Posterior communicating artery B. Anterior choroidal artery C. Superior hypophyseal artery D. Inferior hypophyseal artery

Answer 36

C. Superior hypophyseal artery ## Footnote The supraclinoidal internal carotid artery branches are, from proximal to distal, the ophthalmic, superior hypophyseal, posterior communicating, and anterior choroidal. (D) The inferior hypophyseal artery originates from the intercavernous meningohypophyseal artery, as does the tentorial artery of Bernasconi and Cassinari and the dorsal meningeal artery.

Question 37

The vertebral artery often is divided into numbered segments. What segment exits the axis and curves posteromedially in a groove on the atlas and enters the foramen magnum? A. V2 B. V3 C. V4 D. V5

Answer 37

B. V3 ## Footnote The vertebral artery is divided into four segments. The V1 segment runs from the subclavian artery to the foramen transversarium (usually of the sixth cervical vertebra). The V3 segment runs from the foramen transversarium of C2 to the foramen magnum. (A) The V2 segment runs from C6 to C2. (D) The V4 segment is intradural. (E) There is no V5 segment.

Question 37

What type of nerve ending is slowly adapting? A. Meissner corpuscle B. Pacinian corpuscle C. Merkel disk D. Hair follicle receptor E. A-delta free nerve ending

Answer 37

C. Merkel disk ## Footnote Merkel disks are found in glabrous and hairy skin, hair follicles, and oral mucosa. They are most sensitive to vibrations and they are slowly adapting. (A) Meissner corpuscles are found in skin sensitive to light touch and are rapidly adapting. (B) Pacinian corpuscles are sensitive to vibration and pressure and are rapidly adapting. (D, E) Hair follicle receptors and A-delta free nerve endings are rapidly adapting, whereas C fiber free nerve endings are slowly adapting.

Question 38

What anatomic reference points form the stephanion? A. Junction of the frontal, parietal, temporal, and sphenoid bones B. Junction of the lambdoid, occipitomastoid, and parietomastoid sutures C. Junction of the coronal and sagittal sutures D. Junction of the coronal suture and superior temporal line

Answer 38

D. Junction of the coronal suture and superior temporal line ## Footnote (A) The pterion is at the junction of the frontal, parietal, temporal, and sphenoid bones. (B) The asterion is at the junction of the lambdoid, occipitomastoid, and parietomastoid sutures and often approximates the junction of the transverse and sigmoid sinus. (C) Bregma occurs at the junction of the coronal and sagittal sutures.

Question 39

The stria medullaris thalami connect what neural structures? A. Globus pallidus and the field of Forel H B. Septal nuclei and the habenular nuclei C. Globus pallidus interna and the thalamic fasciculus D. Amygdalae E. Ventral tegmental area and the nucleus accumbens

Answer 39

B. Septal nuclei and the habenular nuclei ## Footnote The stria medullaris thalami (epithalamic structures) connect the septal nuclei along with the anterior thalamic nuclei to the habenula. (A) The ansa lenticularis connects the ventral globus pallidus to the field of Forel H by passing around the posterior limb of the internal capsule. It then joins the lenticular fasciculus to form the thalamic fasciculus. (C) The lenticular fasciculus (field of Forel H2) connects to the thalamic fasciculus in the field of Forel H by passing through the posterior limb of the internal capsule. (D) The anterior commissure connects the amygdalae to one another. (E) The dopaminergic mesolimbic tracts connect the ventral tegmental area to the nucleus accumbens as part of the “reward” circuitry.

Question 40

Corticospinal tracts terminate on which structures in the spinal cord? A. Spinal gray interneurons in Rexed lamina IX B. Alpha motor neurons in Rexed lamina VII C. Gamma motor neurons in the anterior gray horn D. Spinal gray interneurons in Rexed lamina VII E. Gamma motor neurons in Rexed lamina IX

Answer 40

D. Spinal gray interneurons in Rexed lamina VII ## Footnote Corticospinal tracts arise in the cerebral cortex and terminate on the spinal gray interneurons (second-order neurons) that are located in the Rexed lamina VII in the ventral horns. (E) Rexed lamina IX contains alpha and gamma motor neurons.

Question 41

Proprioception sense is carried in what decussating tract? A. Spinothalamic tract B. Posterior columns C. Dorsal spinocerebellar tract D. Ventral spinocerebellar tract E. Corticobulbar tract

Answer 41

D. Ventral spinocerebellar tract ## Footnote The ventral spinocerebellar tract is composed of sensory afferents and carries information about proprioception to the cerebellum. It decussates in the anterior white commissure of the spinal cord and enters the cerebellum through the superior cerebellar peduncle. The fibers then cross within the cerebellum to synapse ipsilateral to the tract origin. (A) The spinothalamic tract is composed of sensory afferents and carries information about pain, temperature, and crude touch. (B) The posterior columns are composed of sensory afferents and carry information about fine touch and proprioception. They are composed of the fasciculi gracilis and fasciculi cuneatus, providing sensory information from the middle thoracic to the lower extremity dermatomes and the cervical (including the upper extremities) to the midthoracic dermatomes, respectively. (C) The dorsal spinocerebellar tract is composed of sensory afferents and carries information about proprioception to the cerebellum. It enters the cerebellum through the inferior cerebellar peduncle without decussating. (E) The corticobulbar tract is composed of motor efferents to the cranial nerve nuclei.

Question 42

The acoustic reflex to loud sound involves what circuitry? A. Cranial nerve V to the tensor veli palatini muscle B. Cranial nerve V to the stapedius muscle C. Cranial nerve V to the levator palatini muscle and cranial nerve VII to the posterior belly of the digastrics muscle D. Cranial nerve V to the tensor tympani muscle and cranial nerve VII to the stapedius muscle

Answer 42

D. Cranial nerve V to the tensor tympani muscle and cranial nerve VII to the stapedius muscle ## Footnote The tensor veli palatini muscle is also innervated by cranial nerve V, whereas the levator palatini muscle is innervated by cranial nerve X. The acoustic reflex is initiated by the superior olivary complex.

Question 43

The transverse component of the transverse ligament of the atlas attaches to what structure? A. Occipital condyle B. Medial surface of the lateral mass of C1 C. Medial surface of the pars interarticularis of C2 D. Posterior aspect of the body of C2 E. Posterior arch of C1

Answer 43

B. Medial surface of the lateral mass of C1 ## Footnote The transverse ligament attaches to the odontoid process and lateral masses of the atlas. (A) The alar ligament connects the dens to the medial surface of the occipital condyles. (D) A portion of the cruciate ligament attaches superiorly to the occipital bone near the tectorial membrane and inferiorly to the posterior aspect of the C2 body. (E) The posterior atlanto-occipital membrane attaches to the posterior arch of C1.

Question 44

Damage to the anterior hypothalamus may cause what dysfunction? A. Obesity B. Cachexia C. Hypothermia D. Impaired memory E. Hyperthermia

Answer 44

E. Hyperthermia ## Footnote The anterior hypothalamus is involved with thermoregulation (cooling) and parasympathetic regulation. Lesions can produce hyperthermia. (A) The ventral medial nucleus is the satiety center. Lesions here will cause obesity. (B) Lesions of the lateral hypothalamus may cause reduced food intake and cachexia. (C) The posterior nucleus is involved in thermoregulation (heating) and sympathetic regulation. Lesions can produce hypothermia and loss of sympathetic tone. (D) Lesions of the mammillary bodies can cause memory deficits and amnestic syndromes.

Question 45

The amygdala projects to which area of the insula? A. Operculum B. Anterior short gyri C. Posterior long gyrus D. Cingulate E. Claustrum

Answer 45

B. Anterior short gyri ## Footnote The insula is composed of an anterior part subdivided into three or four short gyri that receive information from the ventral medial nucleus of the thalamus and amygdala. (A) The frontal, parietal, and temporal opercula surround the insula. (C) The posterior insula is formed by a long gyrus that receives information from the secondary somatosensory cortex and ventral posterior inferior thalamic nucleus. (D) The cingulate is not part of the insula. (E) The claustrum is deep to the insula.

Question 45

What deep cerebellar nucleus is located most laterally? A. Dentate B. Globose C. Fastigial D. Emboliform E. Inferior olivary nucleus

Answer 45

A. Dentate ## Footnote (B) The globose nucleus is lateral to the fastigial nucleus. (C) The fastigial nucleus is the most medially located. (D) The emboliform nucleus is lateral to the globose nucleus. (E) The inferior olivary nucleus is not a deep cerebellar nucleus. It is part of the medulla.

Question 46

What percentage of people have a balanced configuration of the circle of Willis? A. 5% B. 20% C. 40% D. 60% E. 80%

Answer 46

B. 20%

Question 47

The nucleus pulposus is the remnant of what embryonic structure? A. Neural tube B. Anterior neuropore C. Posterior neuropore D. Neural plate E. Notochord

Answer 47

E. Notochord ## Footnote B) The closure of the anterior neuropore results in the creation of the lamina terminalis. Failure to close results in anencephaly. (C) Failure of posterior neuropore closure results in spina bifida.

Question 48

What is the arterial supply for the optic tract? A. Ophthalmic artery B. Anterior communicating, posterior communi- cating, and posterior cerebral arteries **** D. Lateral posterior choroidal artery

Answer 48

C. Posterior communicating, posterior cerebral, and anterior choroidal arteries ## Footnote (A) The ophthalmic artery supplies the retina with blood. (B) The anterior communicating, posterior communicating, and posterior cerebral arteries supply the optic chiasm with blood. (D) The lateral posterior choroidal artery supplies the medial lateral geniculate with blood.

Question 49

What Brodmann area corresponds to primary visual cortex? A. Area 41 B. Area 19 C. Area 17 D. Area 39

Answer 49

C. Area 17 ## Footnote The primary visual cortex resides in Brodmann area 17. (A) Brodmann areas 41 and 42 contain the auditory cortex. (B) Brodmann areas 18 and 19 are the secondary and associative visual cortices. (D) Brodmann area 39 represents the angular gyrus.

Question 50

How many primary ossification centers are present for the C1 (atlas) and C2 (axis) vertebrae, respectively? A. One and three B. Two and four C. Three and five D. Five and three E. Three and one

Answer 50

C. Three and five ## Footnote The C3 through L5 vertebrae have an ossification center in each vertebral body in addition to a center in each half of each neural arch (a total of three for each vertebra). The C1 vertebra has three primary ossification centers: one in the anterior arch and one in each of the lateral posterior arches. The C2 vertebra has five primary ossification centers: the three typical of the other vertebrae in addition to a center on each side of the odontoid process. Secondary ossification centers for the C3 though L5 vertebrae occur at the tip of each spinous process and each transverse process in addition to one at the ring epiphyses at the upper/lower surfaces of each vertebral body (a total of five for each vertebra). The C1 vertebra has no secondary centers, whereas the C2 vertebra has one at the tip of the dens. Failure of this secondary center to fuse results in an os odontoideum.

Question 51

The afferent and efferent projections to and from the medial geniculate body, respectively, are from what structures? A. Superior colliculus; visual cortex B. Retina; visual cortex C. Reticular formation; dorsal thalamic nuclei D. Inferior colliculus; auditory cortex E. Mammillary bodies; cingulum

Answer 51

D. Inferior colliculus; auditory cortex ## Footnote (A) The superior colliculus and visual cortex are the afferent and efferent projections, respectively, to the pulvinar nucleus. (B) The retina and visual cortex are the afferent and efferent projections, respectively, to the lateral geniculate nucleus. (C) The reticular formation and dorsal thalamic nuclei are the afferent and efferent projections, respectively, to the thalamic reticular nucleus. The thalamic reticular nucleus receives input from the cortex, globus pallidus, reticular formation, and dorsal thalamic nuclei. It is the only thalamic nucleus that does not project to the cerebral cortex. (E) The mammillary bodies and cingulum are the afferent and efferent projections, respectively, to the anterior thalamic nucleus (part of the Papez circuit).

Question 52

What blood vessel is at risk of injury during a Chiari decompression? A. Lateral medullary segment of the posterior inferior cerebellar artery B. Telovelotonsillar segment of the posterior inferior cerebellar artery C. Tonsillomedullary segment of the posterior inferior cerebellar artery D. Posterior spinal artery E. V2 segment of the vertebral artery

Answer 52

C. Tonsillomedullary segment of the posterior inferior cerebellar artery ## Footnote The arteries at risk during a Chiari decompression include the vertebral artery (V3 segment as it courses around C1) and the caudal loop of the posterior inferior cerebellar artery (tonsillomedullary segment).

Question 53

Number 2 in this image represents what structure? A. Pars orbitalis B. Premotor gyrus C. Pars triangularis D. Angular gyrus E. Supramarginal gyrus

Answer 53

C. Pars triangularis ## Footnote The inferior frontal gyrus is composed of, from anterior to posterior, the pars orbitalis (1), pars triangularis (2), and pars opercularis (3). The precentral gyrus (4) is found just posterior to the pars opercularis. The sylvian fissure ends posteriorly in the supramarginal gyrus (7). The central sulcus (5) terminates at a gyral bridge near the sylvian fissure. The angular gyrus (8) usually wraps around the superior temporal sulcus. The postcentral gyrus (6) is also shown.

Question 54

The largest intercostal artery is usually found at what location? A. On the left side between the T9 and L2 levels B. On the left side between the T1 and T4 levels C. On the right side between the T9 and L2 levels D. On the right side between the T1 and T4 levels E. On the left side between the L2 and S1 levels

Answer 54

A. On the left side between the T9 and L2 levels ## Footnote The artery of Adamkiewicz is found on the left side in 80% and between the T9 and L2 levels in 85% of individuals. In 15% of individuals, the artery is found between the T5 and T8 levels. It is the main arterial supply to the spinal cord from T8 to the conus medullaris.

Question 55

The Kawase triangle also is known as a triangle by what other name? A. Anteromedial middle cranial fossa triangle B. Anterolateral middle cranial fossa triangle C. Posteromedial middle cranial fossa triangle D. Posterolateral middle cranial fossa triangle E. Infratrochlear middle cranial fossa triangle

Answer 55

C. Posteromedial middle cranial fossa triangle ## Footnote The Kawase triangle is the posteromedial middle cranial fossa triangle. It is bounded by the mandibular nerve (V3), the greater superficial petrosal nerve, the arcuate eminence, and the superior petrosal sinus. It contains the petrous apex, internal auditory canal, vertebrobasilar junction, and cochlea. (A) The Mullan triangle is the anteromedial middle cranial fossa triangle. It is bounded by the ophthalmic nerve (V1), the maxillary nerve (V2), and a line connecting the superior orbital fissure and the foramen rotundum. It contains the sphenoid sinus, ophthalmic vein, and abducens nerve. (B) The anterolateral middle cranial fossa triangle is bounded by the maxillary nerve (V2), the mandibular nerve (V3), and a line connecting the foramen rotundum and the foramen ovale. It contains the lateral sphenoid wing, sphenoid emissary vein, and cavernous to pterygoid venous anastomosis. (D) The Glasscock triangle is the posterolateral middle cranial fossa triangle. It is bounded by the mandibular nerve (V3), the greater superficial petrosal nerve, and a line from the foramen spinosum to the arcuate eminence. It contains the foramen spinosum, horizontal petrous internal carotid artery, and infratemporal fossa. (E) The Parkinson triangle is the infratrochlear middle cranial fossa triangle. It is bounded by a line from the dural entries of the trochlear and abducens nerves, a line from the dural entries of the abducens nerve and the petrosal vein, and the petrous apex. It contains the dural opening to the Meckel cave.

Question 56

What is the typical site and arterial segment involvement of traumatic internal carotid artery dissection? A. At the carotid bifurcation with involvement of the carotid bulb B. At the carotid bifurcation without involve- ment of the carotid bulb C. Two centimeters above the carotid bifurcation with involvement of the carotid bulb D. Two centimeters above the carotid bifurcation without involvement of the carotid bulb E. In the supraclinoidal segment of the internal carotid artery

Answer 56

C. Two centimeters above the carotid bifurcation with involvement of the carotid bulb ## Footnote Typically, the internal carotid artery dissects without involving the carotid bulb. Dissection may cause a Horner syndrome, ipsilateral head or neck pain, and lower cranial nerve neuropathies due to arterial occlusion. (E) The supraclinoidal segment of the internal carotid artery is a less frequent area of dissection.

Question 57

The vertebral arch congenital defect with cystic distention of the meninges and structural/functional abnormalities of the spinal cord/cauda equina is also known by what term? A. Spina bifida occulta B. Myelomeningocele C. Meningocele D. Lipomyelomeningocele E. Diastematomyelia

Answer 57

B. Myelomeningocele ## Footnote (A) Spina bifida occulta is a defect in the vertebral arch without disruption of the underlying meninges. (C) The cystic distention of the meninges without spinal cord/cauda equina involvement is a meningocele. (D) A lipomyelomeningocele is a form of closed spinal dysraphism resulting from a defect in primary neurulation. It is formed by mesenchymal tissue entering a neural placode and forming lipomatous tissue. (E) Diastematomyelia is a postneurulation defect and involves a split spinal cord.

Question 58

Inputs from the dorsal spinocerebellar, cuneocerebellar, vestibulocerebellar, and pontocerebellar tracts are carried by what fibers? A. Climbing B. Mossy C. Parallel D. Purkinje E. Association

Answer 58

B. Mossy ## Footnote (A) Climbing fibers synapse directly on Purkinje cells and originate in the inferior olive. (C) Parallel fibers are the axons to granule cells. (D) Purkinje fibers are conducting fibers of the heart. (E) Association fibers are bundles of axons within the cerebral cortex that unite different parts of the same cerebral hemisphere.

Question 59

What nerve passes through the cavernous sinus and superior orbital fissure but does not go through the annulus of Zinn? A. Superior division of the oculomotor nerve B. Inferior division of the oculomotor nerve C. Abducens nerve D. Trochlear nerve E. Optic nerve

Answer 59

D. Trochlear nerve ## Footnote The mnemonic for remembering the structures that pass through the superior orbital fissure (in order from superior to inferior) is “Little frosty treats sit near icy appetizers.” The lacrimal, frontal, and trochlear nerves all do not pass through the annulus of Zinn, whereas the superior division of the oculomotor, nasociliary, inferior division of the oculomotor, and abducens nerves do. (A–C) These nerves all pass through the cavernous sinus, the superior orbital fissure, and the annulus of Zinn. (E) The optic nerve passes through the annulus of Zinn but is separated from the other nerves by a strut. The optic nerve does not pass throughthe cavernosus sinus or superior orbital fissure.

Question 60

What muscle or muscle group allows for the abduction of the fingers? A. Dorsal interossei B. Lumbricals C. Palmar interossei D. Extensor digitorum E. Flexor digitorum superficialis

Answer 60

A. Dorsal interossei ## Footnote The mnemonic here is “PAD DAB”: palmar interossei adduct, dorsal interossei abduct.” (B) The lumbricals flex the metacarpophalangeal joints while extending the interphalangeal joints, resulting in a “tabletop” action. (C) The palmar interossei adduct the fingers. (D, E) The actions of the extensor digitorum and flexor digitorum superficialis are explained by their names. They do not result in either abduction or adduction of the fingers.

Question 61

The anterior spinal artery arises from what artery or trunk? A. Deep cervical artery B. Costocervical trunk C. Vertebral artery D. Intercostal artery E. Thyrocervical trunk

Answer 61

C. Vertebral artery ## Footnote The anterior spinal artery arises from the junction of two art

Question 62

The long thoracic nerve courses over the surface of what cervical muscle? A. Anterior scalene B. Middle scalene C. Sternocleidomastoid D. Omohyoid E. Longus colli

Answer 62

B. Middle scalene ## Footnote The long thoracic nerve from nerve roots C5, C6, and C7 travels deep to the proximal brachial plexus and between the anterior and middle scalene muscles. It then courses over the posterolateral part of the first rib and innervates the serratus anterior. (A) The phrenic nerve passes over the surface of the anterior scalene as it enters the thorax to innervate the diaphragm.

Question 63

The motor nucleus for the trigeminal nerve is derived from what branchial arch? A. First B. Second C. Third D. Fourth E. Sixth

Answer 63

A. First ## Footnote Pharyngeal/branchial arches develop during the fourth week of embryogenesis as a series of mesodermal outpouchings on both sides of the pharynx. The first arch develops into the muscles of mastication and is related to the trigeminal nerve. (B) The second branchial arch is related to the facial nerve and muscles of facial expression. (C) The third branchial arch is related to the glossopharyngeal nerve and gives rise to the stylopharyngeus. (D) The fourth branchial arch is related to the vagus and superior laryngeal nerves and gives rise to the cricothyroid and all of the intrinsic muscles of the soft palate except for the tensor veli palatini. (E) There is no fifth branchial arch. The sixth branchial arch gives rise to all of the intrinsic muscles of the larynx except for the cricothyroid and is related to the vagus and recurrent laryngeal nerves.

Question 64

What structure extends from the supracondylar process of the humerus to the medial epicondyle? A. Ligament of Struthers B. Arcade of Struthers C. Arcade of Frohse D. Osborne ligament E. Guyon canal

Answer 64

A. Ligament of Struthers ## Footnote The ligament of Struthers is a common site of compression of the median nerve. (B) The arcade of Struthers is a fascial arcade of the intermuscular septum and a potential compression site of the ulnar nerve. It often is released during a cubital tunnel release procedure. (C) The arcade of Frohse is the fibrous proximal border of the supinator muscle and is the most common site of compression of the posterior interosseous nerve. (D) The Osborne ligament connects the two heads of the flexor carpi ulnaris and passes between the olecranon and medial epicondyle, forming the cubital tunnel, which is the most common site of compression of the ulnar nerve. (E) The Guyon canal (near the wrist) forms a distal site of potential ulnar nerve compression. Compression at the Guyon canal can be differentiated from compression at the cubital tunnel, as preservation of the dorsal sensation dermatomes of the ulnar nerve is seen in the latter compression site.

Question 64

The jugular foramen often is divided into two parts: the pars nervosa and the pars vascularis. What structures commonly are found in the anteromedial compartment? A. Cranial nerves IX, X, and XI B. Jugular bulb and inferior petrosal sinus C. Cranial nerve IX, Jacobson’s nerve, and inferior petrosal sinus D. Cranial nerves X and XI, Arnold’s nerve, and jugular bulb E. Cranial nerves IX and X and Jacobson’s nerve

Answer 64

C. Cranial nerve IX, Jacobson’s nerve, and inferior petrosal sinus ## Footnote The anteromedial compartment (pars nervosa) is smaller and consists of cranial nerve IX, the Jacobson nerve (tympanic nerve of cranial nerve IX, providing sensation to the middle ear and parasympathetics through the lesser petrosal nerve to the otic ganglion and parotid gland), and the inferior petrosal sinus. The mnemonic is “nervous nine” to remember the relationship of the pars nervosa to the cranial nerve IX components. (D) The larger, posterolateral compartment (pars vascularis) contains cranial nerves X and XI, the Arnold nerve ( involved in sensation of the skin of the ear canal and in the ear–cough reflex), the jugular bulb, and a branch of the ascending pharyngeal artery.

Question 65

What is the only circumventricular organ that contains an intact blood–brain barrier? A. Median eminence B. Organ of the lamina terminalis C. Subfornical organ D. Area postrema E. Subcommissural organ

Answer 65

E. Subcommissural organ ## Footnote Circumventricular organs are characterized by their proximity to the ventricles and their lack of a blood–brain barrier. They include the area postrema, subfornical organ, organ of the lamina terminalis, subcommissural organ, posterior pituitary gland, pineal gland, median eminence, and intermediate lobe of the pituitary gland. The subcommissural organ has an intact blood–brain barrier but is considered a circumventricular organ, given its role in the neuroendocrine system. Overall, its function largely is unknown. (D) The area postrema is the only paired circumventricular organ.

Question 66

With respect to cytoarchitecture of the isocortex, what layer contains afferent fibers from the thalamus? A. External granular B. Internal granular C. External pyramidal D. Internal pyramidal E. Multiform

Answer 66

B. Internal granular ## Footnote Layer 1 is the molecular layer and is the most superficial. Layer 4 is the internal granular layer and receives afferent fibers from the thalamus. (A,177 C) Layers 2 and 3 are the external granular and external pyramidal layers, respectively, and contain commissural/association fibers. (D) Layer 5 is the internal pyramidal layer and contains Betz cells that are the main efferents to the brainstem and spinal cord. (E) Layer 6 is the multiform layer that sends fibers to the thalamus.

Question 67

Corpus striatum refers to what structure(s)? A. Caudate and putamen B. Caudate, putamen, and globus pallidus C. Putamen and globus pallidus D. Caudate E. Caudate and globus pallidus

Answer 67

B. Caudate, putamen, and globus pallidus ## Footnote (A) Striatum refers to the caudate and putamen. (C) Lentiform nuclei refer to the putamen and globus pallidus. (D) Neostriatum refers to the caudate.

Question 68

What cistern contains the anterior choroidal artery, posterior cerebral artery, medial posterior choroidal artery, and basal vein of Rosenthal? A. Ambient B. Quadrigeminal C. Interpeduncular D. Carotid E. Crural

Answer 68

E. Crural ## Footnote (A) The ambient cistern contains the anterior choroidal artery, basal vein of Rosenthal, and posterior cerebral artery. (B) The quadrigeminal cistern contains the superior cerebellar artery, cranial nerve IV, precentral vein, vein of Galen, and posterior cerebral artery. (C) The interpeduncular cistern contains the basilar artery, cranial nerve III, posterior cerebral artery, and superior cerebellar artery. (D) The carotid cistern contains the internal carotid artery, anterior choroidal artery, and posterior communicating artery.

Question 69

The neurohypophysis contains axons that transport precursors of what hormones? A. Adrenocorticotropic and thyroid-stimulating hormones B. Luteinizing and follicle-stimulating hormones C. Growth hormone and prolactin D. Oxytocin and antidiuretic hormone E. Oxytocin and growth hormone

Answer 69

D. Oxytocin and antidiuretic hormone ## Footnote he posterior pituitary (neurohypophysis) releases oxytocin and vasopressin (antidiuretic hormone) derived from supraoptic and paraventricular neurons in the hypothalamus. The anterior pituitary (adenohypophysis) contains releasing factors and inhibitory hormones such as corticotrophin-releasing, thyrotropin-releasing, gonadotropin-releasing, growth hormone–releasing/inhibiting, and prolactin-releasing/inhibiting hormones that release adrenocorticotropic, thyroid-stimulating, luteinizing, follicle-stimulating, growth, and prolactin hormones, respectively.

Question 70

Which structure forms the roof of the temporal horn? A. Amygdala B. Hippocampus C. Tapetum D. Choroidal fissure E. Collateral eminence

Answer 70

C. Tapetum ## Footnote The roof and lateral wall of the temporal horn are composed primarily of the tapetum of the corpus callosum and are enveloped by optic radiations. (A) The anterior wall of the temporal horn is formed by the amygdala. (B) The floor of the temporal horn is formed largely by the hippocampus. (D) The choroidal fissure is located along the medial wall of the temporal horn. (E) The collateral eminence forms part of the floor of the temporal horn and lies lateral and parallel to the hippocampus.

Question 71

The spinocerebellar tract (SCT) conveys proprioceptive information from the body to the cerebellum. Which pathway is correct? A. Fibers from the ventral SCT often cross contra- laterally in the spinal cord and cross again con- tralaterally in the superior cerebellar peduncle to reach the cerebellum B. Fibers entering the dorsal SCT synapse in the Clarke column and then ascend to travel to the cerebellum through the contralateral inferior cerebellar peduncle. C. Fibers entering the ventral SCT often cross con- tralaterally in the spinal cord and cross again contralaterally in the inferior cerebellar pe- duncle to reach the cerebellum. D. Fibers entering the dorsal SCT cross contralat- erally in the spinal cord and then ascend to travel to the cerebellum through the contralat- eral superior cerebellar peduncle. E. Fibers entering the ventral SCT synapse in the Clarke column and then ascend to travel to the cerebellum through the ipsilateral inferior cerebellar peduncle.

Answer 71

A. Fibers from the ventral SCT often cross contra- laterally in the spinal cord and cross again con- tralaterally in the superior cerebellar peduncle to reach the cerebellum ## Footnote A Fibers from the ventral SCT often cross contralaterally in the spinal cord and cross again contralaterally in the superior cerebellar peduncle to reach the cerebellum. The dorsal spinocerebellar tract (SCT) synapses in the Clarke nuclei (Rexed lamina VII) and then ascends ipsilaterally to reach the cerebellum through the inferior cerebellar peduncle. It is an ipsilateral tract. In contrast, the ventral SCT synapses in Rexed laminae V, VI, and VII before crossing contralaterally through the anterior commissure to continue its ascent. Most fibers cross contralaterally (although some fibers continue ipsilaterally) through the superior cerebellar peduncle to reach the cerebellum. It is an ipsilateral tract with a double crossing.

Question 72

Where do climbing fibers originate? A. Vestibular nucleus B. Dentate nucleus C. Cerebellar glomeruli D. Inferior and superior colliculi E. Inferior olivary nucleus

Answer 72

E. Inferior olivary nucleus ## Footnote Climbing fibers synapse on Purkinje cells after originating in the inferior olivary nucleus of the medulla and are among the most excitatory fibers in the central nervous system. (A) Pontine and vestibular nuclei form mossy fibers. (C) The spinal cord and reticular formation send projections that end in cerebellar glomeruli.

Question 73

What extraocular muscle is innervated by a contralateral nucleus? A. Inferior oblique B. Inferior rectus C. Superior rectus D. Medial rectus E. Lateral rectus

Answer 73

C. Superior rectus ## Footnote There are three extraocular muscles that are innervated by contralateral nuclei. The superior oblique is innervated by the trochlear nerve, which crosses within the midbrain and emerges contralaterally from its nucleus from the dorsal surface of the brainstem. The levator palpebrae superioris is innervated bilaterally by the caudal subnucleus. In addition, the medial subnucleus of cranial nerve III provides innervation to the contralateral superior rectus muscle.

Question 73

What brain structure is rich in acetylcholine? A. Locus coeruleus B. Raphe nucleus C. Basal nucleus of Meynert D. Substantia nigra E. Suprachiasmatic nucleus

Answer 73

C. Basal nucleus of Meynert ## Footnote The basal nucleus of Meynert is found in the basal forebrain (substantia innominata) and is rich in acetylcholine. The nucleus is important in visual attention. (A) The locus coeruleus is a pontine structure rich in norepinephrine. (B) The raphe nucleus is found in the brainstem and is rich in serotonin. (D) The substantia nigra is found in the midbrain and is rich in dopamine. (E) The suprachiasmatic nucleus is involved in the production of cortisol and melatonin for mediation of circadian rhythms.

Question 73

What Rexed lamina contains motor neurons? A. II B. IV C. VII D. IX E. X

Answer 73

D. IX ## Footnote The gray matter of the spinal cord is divided into 10 Rexed laminae. The sensory areas are the most dorsal, whereas the motor areas are the most ventral. Laminae VIII and IX contain medial and lateral motor neuron columns (flexor muscle neurons are located more medially than extensor muscle neurons). (A) Lamina II is known as the substantia gelatinosa and responds to noxious pain. There is a high concentration of substance P in lamina II. (B) Lamina IV is known as the nucleus proprius and is involved in proprioception and light touch. (C) Lamina VII is a large zone that contains a group of interneurons known as the dorsal nucleus (Clarke column) that give rise to the posterior spinocerebellar tract and the intermediolateral nucleus (levels T1 through L2), with the latter containing preganglionic sympathetic neurons. (E) Lamina X is the gray matter surrounding the central canal.

Question 74

What are Renshaw cells? A. Inhibitory interneurons found in the spinal cord that release GABA B. Inhibitory interneurons found in the spinal cord that release glycine C. Excitatory interneurons found in the spinal cord that release glutamate D. Excitatory interneurons found in the spinal cord that release acetylcholine E. Inhibitory interneurons found in the brain- stem that releases GABA

Answer 74

B. Inhibitory interneurons found in the spinal cord that release glycine ## Footnote Renshaw cells are interneurons located in the ventral horn of the spinal cord that project to alpha motor neurons. They are stimulated by acetylcholine and release inhibitory glycine.

Question 75

Schaffer collateral branches consist of what fibers? A. Fibers projecting from CA3 to CA1 B. Fibers projecting from CA3 to the fornix C. Fibers projecting from the dentate gyrus to CA3 D. Fibers projecting from the cingulum to the parahippocampal gyrus E. Fibers projecting from the lateral olfactory stria to the pyriform cortex

Answer 75

A. Fibers projecting from CA3 to CA1 ## Footnote In addition to projecting to the fornix, CA3 neurons project to CA1 (the Sommer sector) as Schaffer collaterals. (B) The CA3 neurons transmit information to the fornix, which is the major efferent pathway for the hippocampus. (C) Fibers enter the hippocampus from the dentate gyrus and project to neurons in CA3. (D) Fibers projecting from the cingulate gyrus to the parahippocampus are part of the Papez circuit (parahippocampus to the hippocampus to the fornix to the mammillary bodies to the anterior thalamus to the cingulate to the parahippocampus). (E) The pyriform cortex, entorhinal cortex, and amygdala are part of the olfactory projection area. The pyriform cortex projects to the thalamus and frontal lobe.

Question 76

What two veins provide immediate contributions to the vein of Galen? A. Anterior septal and thalamostriate veins B. Inferior sagittal sinus and internal cerebral vein C. Superior sagittal and straight sinuses D. Basal vein of Rosenthal and internal cerebral vein E. Basal vein of Rosenthal and straight sinus

Answer 76

D. Basal vein of Rosenthal and internal cerebral vein ## Footnote The two internal cerebral veins join with their respective basal veins of Rosenthal to form the great cerebral vein (of Galen). The vein of Galen also receives drainage from callosal, superior cerebellar, and inferior cerebral veins. (A) The thalamostriate and septal veins join to form the internal cerebral vein. (B) The vein of Galen and the inferior sagittal sinus merge to form the straight sinus. (E) The straight and superior sagittal sinuses form the torcular.

Question 77

A patient with a stroke of the occipital lobe sparing the most caudal area of the visual cortex would have what visual findings? A. Congruent homonymous hemianopsia with- out sparing of central vision B. Congruent homonymous hemianopsia with sparing of central vision C. Incongruent homonymous hemianopsia D. Bitemporal hemianopsia E. Junctional scotoma

Answer 77

B. Congruent homonymous hemianopsia with sparing of central vision ## Footnote The most caudal area of the visual cortex represents central vision. Lesions affecting the visual cortex with macular sparing can be seen in some cases of posterior cerebral artery infarction due to the middle cerebral artery collaterals supplying the most caudal areas that concern central vision. With diffuse anoxic states, central vision can be affected before or along with the rest of the visual cortex due to the central visual cortex being so far distal in the circulation. A visual cortex lesion produces a homonymous hemianopsia that tends to be much more congruent than optic tract lesions. (C) Incongruent homonymous hemianopsias are due to unilateral optic tract compressions proximal to the thalamus. (D, E) Bitemporal hemianopsia and junctional scotomas are seen with chiasmal compression, with the latter attributed to compression of the Wilbrand knee in the anterior chiasm. A more contemporary theory about the etiology of junctional scotomas is that they are the result of an asymmetric anterior chiasm compression causing an optic neuropathy and scotoma in one eye and a contralateral superotemporal deficit in the other eye.

Question 78

The vertical crest (Bill’s bar) separates what two structures? A. Facial nerve and cochlear nerve B. Superior vestibular nerve and inferior vestibu- lar nerve C. Cochlea and anteromedial turn of the carotid D. Facial nerve and superior vestibular nerve E. Pars nervosa and pars vascularis of the jugular foramen

Answer 78

D. Facial nerve and superior vestibular nerve ## Footnote The facial, cochlear, and inferior and superior vestibular nerves are found in the lateral internal auditory canal. In the lateral portion of the canal, the horizontal (falciform) crest separates the facial and superior vestibular nerves superiorly from the cochlear and inferior vestibular nerves inferiorly. Vertically, the vertical crest (Bill’s bar) separates the facial nerve (anterior/superior) from the superior vestibular nerve (posterior/superior). The mnemonic is “7 Up,” indicating that cranial nerve VII is in the superior portion of the canal. The “superior” in superior vestibular nerve describes its position in the canal relative to the inferior vestibular nerve. (A, B) The facial and cochlear nerves are separated by the horizontal crest as are the superior and inferior vestibular nerves.

Question 79

The nasociliary nerve innervates what areas/ structures? A. Lacrimal gland B. Ethmoid sinuses C. Forehead and frontal sinuses D. Iris dilator muscle E. Cornea

Answer 79

B. Ethmoid sinuses ## Footnote The ethmoid sinuses are innervated by the nasociliary nerve through the posterior ethmoidal nerve. (A) The lacrimal gland is innervated by the lacrimal nerve. (C) The forehead and frontal sinuses are innervated by the frontal nerve. (D) The iris dilator muscle is innervated by sympathetic nerves following the ciliary nerves. (E) The cornea is innervated by the ophthalmic division of the trigeminal nerve through the ciliary nerves.

Question 80

What connective tissue structure prevents separation of the sciatic nerve into fascicles? A. Perineurium B. Endoneurium C. Epineurium D. Deep fascia E. Superficial fascia

Answer 80

C. Epineurium ## Footnote The epineurium surrounds multiple fascicles and the vessels supplying the fascicles with blood. (A) The perineurium surrounds each fascicle (a bundle of individual nerve fibers). (B) The endoneurium is the connective tissue that surrounds each myelinated nerve fiber.