CHAPTER 13 Flashcards
- A 50-year-old family physician has vertical
diplopia; the man feels unsure when descend-
ing stairs. He can eliminate the double vision
by tilting his chin toward the paretic side.
Which of the following extraocular muscles is
responsible for the ocular malalignment?
(A) Superior rectus
(B) Inferior rectus
(C) Inferior oblique
(D) Lateral rectus
(E) Superior oblique
l-E. The superior oblique muscle depresses, abducts, and intorts the eye. Paralysis of this mus-
cle results in extorsion and weakness of downward gaze. Head tilting compensates for extorsion.
- A chemodectoma of the glomus jugulare
comprises all of the cranial nerves passing
through the jugular foramen. All of the follow-
ing functions would be ipsilaterally impaired
as a result of this tumor EXCEPT
(A) the gag reflex
(B) parotid gland secretion
(C) phonation
(D) swallowing
(E) normal movement of the tongue
2-E. The hypoglossal nerve (CN XII) passes through the hypoglossal canal, not through the
jugular foramen. It innervates the intrinsic and extrinsic muscles of the tongue (genioglossus,
styloglossus, and hyoglossus).
3. The cavernous sinus contains all of the fol- lowing structures EXCEPT the (A) ophthalmic nerve (B) mandibular nerve (C) abducent and trochlear nerves (D) postganglionic sympathetic fibers (E) preganglionic parasympathetic fibers
3-B. The mandibular nerve (CN V-3) does not pass through the cavernous sinus; it exits the skull
via the foramen ovale.
4. The superior orbital fissure contains all of the following structures EXCEPT the (A) ophthalmic veins (B) ophthalmic nerve (C) trochlear nerve (D) abducent nerve (E) optic nerve
4-E. The optic nerve (CN II) enters the skull via the optic canal. The optic canal also contains
the ophthalmic artery.
- Transection of the left oculomotor nerve re-
sults in all of the following conditions EXCEPT
(A) diplopia when attempting to adduct the
left eye
(B) a fixed dilated pupil on the left side
(C) no consensual reaction when light is shone
in the left eye
(D) a normal bilateral corneal reflex
(E) a left eye that “looks down and out”
the ophthalmic artery.
5-C. Transection of the oculomotor nerve (CN III) does not interrupt the afferent limb of the
pupillary reflex, which is bilateral. Light shone into the left eye results in constriction of the con-
tralateral pupil, the consensual reaction.
- A glioma destroying the right trochlear nu-
cleus would result in all of the following condi-
tions EXCEPT
(A) extorsion of the affected eye
(B) diplopia when looking down
(C) head tilt
(D) paralysis of the right superior oblique
muscle
(E) unaffected pupillary light reflexes
6-D. The right trochlear nucleus of CN IV projects to the left superior oblique muscle. Diplopia
occurs when an image falls on disparate parts of the retina. The pupillary light reflex is medi-
ated by the parasympathetic fibers of the oculomotor nerve
- All of the following statements concerning
the vestibulocochlear nerve are correct EXCEPT
(A) it exits the brainstem in the cerebellopon-
tine (CP) angle
(B) the vestibular ganglion is located in the
internal auditory meatus
(C) irritative lesions cause tinnitus and nys-
tagmus
(D) destructive lesions cause ipsilateral deaf-
ness
(E) it is a special visceral afferent (SVA) nerve
7-E. The vestibulocochlear nerve (CN VIII) is classified as a special somatic afferent (SSA)
nerve, as is the optic nerve (CN II).
- All of the following statements concerning
the geniculate ganglion are correct EXCEPT
(A) it is found within the temporal bone
(B) it receives taste fibers from the anterior
two-thirds of the tongue
(C) it gives rise to the greater petrosal nerve
(D) it contains postganglionic parasympathetic
neurons
(E) it contains sensory neurons that inner-
vate the outer ear
8-D. The geniculate ganglion contains all of the first-order sensory neurons of the facial nerve
(CN VII) [general somatic afferent (GSA) and special visceral afferent (SVA)]. It is found within
the temporal bone and gives rise to the greater petrosal nerve. Sensory neurons in the genicu-
late ganglion innervate taste buds from the anterior two-thirds of the tongue. Taste fibers from
the posterior third of the tongue belong to the glossopharyngeal nerve (CN IX). Pseudounipolar
ganglion cells of the geniculate ganglion innervate part of the outer ear.
- All of the following statements concerning
the olfactory nerve are correct EXCEPT
(A) it projects directly to the forebrain
(B) it synapses with mitral cells
(C) its cells of origin are found in the nasal
mucosa
(D) it is a special somatic afferent (SSA) nerve
(E) it enters the skull via the cribriform plate
of the ethmoid bone
9-D. The olfactory nerve (CN I), a special visceral afferent (SVA) nerve, consists of the un-
myelinated axons of bipolar neurons found in the olfactory epithelium of the upper nasal cavity.
There are 25 million neurosensory cells on each side. These axons synapse with mitral cells in
the olfactory bulb, a rhinencephalic structure of the forebrain. Mitral cells project directly via the
olfactory tract to the primary olfactory cortex of the uncus.
- All of the following statements concerning
the optic nerve are correct EXCEPT
(A) it enters the skull via the superior orbital
fissure
(B) it is the afferent limb of the pupillary light
reflex
(C) there is no regeneration after injury
(D) it lies within the subarachnoid space
(E) its axons are myelinated by oligodendro-
cytes
10-A. The optic nerve (CN II) enters the skull via the optic canal of the sphenoid bone (the oph-
thalmic artery is also found in the optic canal). Efferent retinal fibers are the afferent limb of the
pupillary light reflex. The efferent limb is the oculomotor nerve (CN III). The optic nerve is in-
vested with meninges and lies in the subarachnoid space. The optic nerve is a tract of the cen-
tral nervous system (CNS) and not a peripheral nerve. There is no regeneration after transec-
tion. The axons of the optic nerve are myelinated by oligodendrocytes; peripheral nerve axons
are myelinated by Schwann cells.
- All of the following statements concerning
the oculomotor nerve are correct EXCEPT
(A) it originates in the rostral midbrain
(B) it traverses the cavernous sinus
(C) it exits the cranial vault via the superior
orbital fissure
(D) it has a sympathetic component
(E) transection results in ptosis
11-D. The oculomotor nucleus is found in the rostral midbrain at the level of the superior col-
liculus. Ptosis results after transection of the fibers to the levator palpebrae muscle. The oculo-
motor nerve (CN III) traverses the wall of the cavernous sinus with CN IV, CN VI, CN V-l, and
CN V-2. The oculomotor nerve has a general visceral efferent (GVE) parasympathetic component,
which arises from the Edinger-Westphal nucleus. CN III exits the cranium via the superior or-
bital fissure.
- All of the following statements concerning
the accessory nerve are correct EXCEPT
(A) it exits the skull via the jugular foramen
(B) it contains fibers from the nucleus am-
biguus
(C) it contains fibers from the dorsal motor
nucleus
(D) it contains fibers from cervical spinal cord
levels
(E) it innervates two muscles of branchiomeric
origin
12-C. The accessory (spinal) nerve (CN XI) exits the skull via the jugular foramen (with CN IX
and CN X). The spinal part of the spinal accessory nerve enters the skull via the foramen mag-
num. CN XI contains SVE fibers from the nucleus ambiguus that innervate intrinsic muscles of
the larynx; CN XI contains special visceral efferent (SVE) fibers from the cervical spinal cord that 12-C. The accessory (spinal) nerve (CN XI) exits the skull via the jugular foramen (with CN IX
and CN X). The spinal part of the spinal accessory nerve enters the skull via the foramen mag-
num. CN XI contains SVE fibers from the nucleus ambiguus that innervate intrinsic muscles of
the larynx; CN XI contains special visceral efferent (SVE) fibers from the cervical spinal cord that innervate two muscles of branchiomeric origin—the trapezius and the sternocleidomastoid. The
dorsal motor nucleus is the general visceral efferent (GVE) nucleus of the vagal nerve (CN X).
- All of the following statements concerning
the facial nerve are correct EXCEPT
(A) it innervates the lacrimal gland
(B) it innervates the stapedius muscle
(C) it innervates the posterior belly of the di-
gastric muscle
(D) it provides the efferent limb for the
corneal reflex
(E) it projects to the otic ganglion
13-E. The facial nerve (CN VII) provides the preganglionic parasympathetic innervation for the
lacrimal, sublingual, and submandibular glands and innervates the stapedius muscle of the tym-
panic cavity and the posterior belly of the digastric muscle. The otic ganglion receives pregan-
glionic parasympathetic input from the glossopharyngeal nerve (CN IX) and projects postgan-
glionic parasympathetic fibers to the parotid gland.
- All of the following statements concerning
the trigeminal nerve are correct EXCEPT
(A) it contains special visceral efferent (SVE)
and general somatic afferent (GSA) fibers
(B) it innervates the tensor tympani muscle
(C) it innervates the anterior belly of the di-
gastric muscle
(D) it innervates the supratentorial dura
(E) it innervates the skin over the angle of the
jaw
14-E. The trigeminal nerve (CN V) [general somatic afferent (GSA) and special visceral effer-
ent (SVE)] innervates the tensor tympani muscle, the anterior belly of the digastric muscle, and
the supratentorial dura. The skin over the angle of the jaw and the scalp of the back of the head
are innervated by the second and third cervical nerves.
- Transection of the glossopharyngeal nerve
results in all of the following deficits EXCEPT
(A) loss of the gag reflex
(B) loss of neurons in the superior salivatory
nucleus
(C) loss of taste and pain sensation from the
posterior third of the tongue
(D) loss of the carotid sinus reflex
(E) loss of neurons in the nucleus ambiguus
15-B. Transection of the glossopharyngeal nerve (CN IX) results in degeneration of neurons in
the rostral part of the nucleus ambiguus and in the inferior salivatory nucleus, loss of the gag re-
flex, loss of sensation from the tonsillar bed, loss of taste and pain sensation from the posterior
third of the tongue, and loss of the carotid sinus reflex. The superior salivatory nucleus is a gen-
eral visceral efferent (GVE) nucleus of CN VII.
