CHAPTER 5 - Book Review Questions

Question 1

The following general statements concern the medulla oblongata:

(a) The caudal half of the floor of the fourth ventricle is formed by the rostral half of the medulla.
(b) The central canal extends throughout the length
of the medulla oblongata.
(c) The nucleus gracilis situated beneath the gracile tubercle on the anterior surface of the medulla.
(d) The decussation of the medial lemnisci takes
place in the rostral half of the medulla
(e) The cerebellum lies anterior to the medulla.

Answer 1

A is correct.

• The caudal half of the floor of the fourth ventricle is formed by the rostral half of the medulla oblongata (see Fig. 5-9). B. The central canal in the medulla oblongata is limited to the caudal half. C. The nucleus gracilis is situated beneath the gracile tubercle on the posterior surface of the medulla. D. The decussatlon of the medial lemnisci takes place in the caudal half of the medulla. E. The cerebellum lies posterior to the medulla.

Question 2

The following statements concern the interior of the lower part of the medulla:

(a) The decussation of the pyramids represents the
crossing over from one side of the medulla to
the other of a quarter of the corticospinal fibers.
(b) The central canal of the spinal cord is not continuous upward into the medulla.
(c) The substantia gelatinosa is not continuous
with the nucleus of the spinal tract of the trigeminal nerve.
(d) The medial lemniscus is formed by the anterior spinothalamic tract and the spinotectal tract.
(e) The internal arcuate fibers emerge from the nucleus gracilis and nucleus cuneatus.

Answer 2

E is correct.

• The internal arcuate fibers emerge from the nucleus gracilis and nucleus cuneatus (see Fig. 4-16). A. The decussation of the pyramids represents the crossing over from one side of the medulla to the other of three fourths of the corticospinal fibers. B. The central canal of the spinal cord is continuous upward into the medulla. C. The substantia gelatinosa becomes continuous with the nucleus of the spinal part of the trigeminal nerve. D. The medial lemniscus is formed by the axons of cells in the nucleus gracilis and the nucleus cuneatus; the axons leave the nuclei and cross the midline as the internal arcuate fibers and then ascend to the thalamus (see Fig. 4-16).

Question 3

The following statements concern the interior of the upper part of the medulla:

(a) The reticular formation consists of nerve fibers
but no nerve cells.
(b) The nucleus ambiguus constitutes the motor
nucleus of the vagus, cranial part of the accessory, and hypoglossal nerves.
(c) Beneath the floor of the fourth ventricle are
located the dorsal nucleus of the vagus and the
vestibular nuclei.
(d) The medial longitudinal fasciculus is a bundle
of ascending fibers on each side of the midline.
(e) The inferior cerebellar peduncle connects the
pons to the cerebellum.

Answer 3

C is correct.

• Beneath the floor of the fourth ventricle are located the dorsal nucleus of the vagus and the vestibular nuclei (see Fig. 5-14). A. The reticular formation in the upper part of the medulla oblongata consists of a mixture of nerve fibers and small nerve cells. B. The nucleus ambiguus constitutes the motor nucleus of the glossopharyngeal, vagus, and the cranial part of the accessory nerves. D. The medial longitudinal fasciculus is a bundle of ascending and descending fibers that Iie posterior to the medial lemniscus on each side of the midline (see Fig. 5-14). E. The inferior cerebellar peduncle connects the medulla to the cerebellum.

Question 4

The following statements concern the Arnold-Chiari phenomenon:

(a) It is an acquired anomaly.
(b) The exits in the roof of the fourth ventricle may
be blocked.
(c) The cerebellum never herniates through the
foramen magnum.
(d) It is not associated with various forms of spina
bifida.
(e) Performing a spinal tap in this condition is safe.

Answer 4

B is correct.

• In the Arnold-Chiari phenomenon, the exits in the roof of the fourth ventricle may be blocked. A. It is a congenital anomaly. C. The tonsil of the cerebellum may herniate through the foramen magnum (see Fig. 5-30). D. The Arnold-Chiari phenomenon is commonly associated with various forms of spina bifida. E. Performing a spinal tap in the setting of this condition is very dangerous.

Question 5

The following statements concern the medial medullary syndrome:

(a) The tongue is paralyzed on the contralateral side.
(b) Ipsilateral hemiplegia is evident.
(c) Ipsilateral sensations of position and movement are impaired.
(d) It is commonly caused by thrombosis of a branch of the vertebral artery to the medulla oblongata.
(e) Contralateral facial paralysis Is evident.

Answer 5

D is correct.

• The medial medullary syndrome is commonly caused by thrombosis of a branch of the vertebral artery to the medulla oblongata. A. The tongue is paralyzed on the ipsilateral side. B. Contralateral hemiplegla is evident. C. Contralateral impaired sensations of position and movement are evident. E. Facial paralysis is not evident.

Question 6

The following statements concern the lateral medullary syndrome:

(a) It may be caused by a thrombosis of the
anterior inferior cerebellar artery.
(b) The nucleus ambiguus of the same side may be
damaged.
(c) Analgesia and thermoanesthesia may be evident
on the contralateral side of the face.
(d) Contralateral trunk and extremity hypalgesia
and thermoanesthesia may occur.
(e) Seizures may occur.

Answer 6

B is correct.

• In the lateral medullary syndrome, the nucleus ambiguus of the same side may be damaged. A. The condition may be caused by thrombosis of the posterior inferior cerebellar artery. C. Analgesia and thermoanesthesia on the ipsilateral side of the face may occur. D. lpsilateral trunk and extremity hypalgesia and thermoanesthesia may occur. E. Seizures usually do not occur.

Question 7

The following statements concern the pons:

(a) The trigeminal nerve emerges on the lateral aspect of the pons.
(b) The glossopharyngeal nerve emerges on the
anterior aspect of the brainstem in the groove
between the pons and the medulla oblongata.
(c) The basilar artery lies in a centrally placed
groove on the anterior aspect of the pons.
(d) Many nerve fibers present on the posterior aspect of the pons converge laterally to form the middle cerebellar peduncle.
(e) The pons forms the lower half of the floor of the fourth ventricle.

Answer 7

C is correct.

• The basilar artery lies in a centrally
  placed groove on the anterior aspect of the pons. A. The trigeminal nerve emerges on the anterior aspect of the pons. B. The glossopharyngeal nerve emerges on the anterior aspect of the medulla oblongata in the groove between the olive and the inferior cerebellar peduncle (see Fig. 5-9). D. The nerve fibers on the anterior aspect of the pons converge laterally to form the middle cerebellar peduncle. E. The pons forms the upper half of the floor of the fourth ventricle (see Fig. 5-18).

Question 8

The following important structures are located in the brainstem at the level stated:

(a) The red nucleus lies within the midbrain.
(b) The facial colliculus lies in the cranial part of the pons.
(c) The motor nucleus of the trigeminal nerve lies
within the caudal part of the pons.
(d) The abducens nucleus Iies within the cranial
part of the pons.
(e) The trochlear nucleus lies within the midbrain
at the level of the superior colliculus.

Answer 8

A is correct.

• The red nucleus lies within the midbrain (see Fig. 5-25). B. The facial colliculus lies in the caudal part of the pons (see Fig. 5-18). C. The motor nucleus of the trigeminal nerve lies within the cranial part of the pons (see Fig. 5-20). D. The abducens nucleus lies within the caudal part of the pons (see Fig. 5-19). E. The trochlear nucleus Iies within the midbrain at the level of the inferior colliculus (see Fig. 5-25).

Question 9

The following statements concern the posterior surface of the pons:

(a) Lateral to the median sulcus is an elongated
swelling called the lateral eminence.
(b) The facial colliculus is produced by the root of the facial nerve winding around the nucleus
of the abducens nerve.
(c) The floor of the inferior part of the sulcus limitans is pigmented and is called the substantia
ferruginea.
(d) The vestibular area lies medial to the sulcus
limitans.
(e) The cerebellum lies anterior to the pons.

Answer 9

B is correct.

• On the posterior surface of the pons is the facial colliculus, which is produced by the root of the facial nerve winding around the nucleus of the abducens nerve (see Fig. 5-19). A. The medial eminence is an elongated swelling lateral to the median sulcus (see Fig. 5-26). C. The floor of the superior part of the sulcus limitans is pigmented and is called the substantia ferruginea (see Fig. 5-18). D. The vestibular area Iies lateral to the sulcus limitans (see Fig. 5-18). E. The cerebellum lies posterior to the pons.

Question 10

The following statements concern a transverse section through the caudal part of the pons:

(a) The pontine nuclei Iie between the transverse
pontine fibers.
(b) The vestibular nuclei lie medial to the abducens
nucleus.
(c) The trapezoid body is made up of fibers derived
from the facial nerve nuclei.
(d) The tegmentum is the part of the pons lying
anterior to the trapezoid body.
(e) The medial longitudinal fasciculus lies above
the floor of the fourth ventricle on either side
of the midline.

Answer 10

A is correct.

• The pontine nuclei lie between the transverse pontine fibers (see Fig. 5-12). B. The vestibular nuclei lie lateral to the abducens nucleus (see Fig. 5-19). C. The trapezoid body is made up of fibers derived from the cochlear nuclei and the nuclei of the trapezoid body. D. The tegmentum is the part of the pons lying posterior to the trapezoid body. E. The medial longitudinal fasciculus lies below the floor of the fourth ventricle on either side of the midline (see Fig. 5-19).

Question 11

The following statements concern a transverse section through the cranial part of the pons:

(a) The motor nucleus of the trigeminal nerve lies lateral to the main sensory nucleus in the tegmentum.
(b) The medial lemniscus has rotated so that its
long axis lies vertically.
(c) Bundles of corticospinal fibers lie among the
transverse pontine fibers.
(d) The medial longitudinal fasciculus joins the
thalamus to the spinal nucleus of the trigeminal
nerve.
(e) The motor root of the trigeminal nerve is much
larger than the sensory root.

Answer 11

C is correct.

• In the pons, bundles of corticopontine fibers lie among the transverse pontine fibers (see Fig. 5-19). A. The motor nucleus of the trigeminal nerve lies medial to the main sensory nucleus in the tegmentum of the pons (see Fig. 5-20). B. In the cranial part of the pons, the medial lemniscus has rotated so that its long axis lies transversely (see Fig. 5-20). D. The medial longitudinal fasciculus is the main pathway that connects the vestibular and cochlear nuclei with the nuclei controlling the extraocular muscles (oculomotor, trochlear, and abducens nuclei). E. The motor root of the trigeminal nerve is much smaller than the sensory root.

Question 12

The following statements concern the pons:

(a) It is related superiorly to the dorsum sellae of the sphenoid bone.
(b) It lies in the middle cranial fossa.
(c) Glial tumors of the pons are rare.
(d) The corticopontine fibers terminate in the pontine nuclei.
(e) The pons receives its blood supply from the
internal carotid artery.

Answer 12

D is correct.

• In the pons, the corticopontine fibers terminate in the pontine nuclei. A. The pons is related anteriorly to the dorsum sellae of the sphenoid bone. B. The pons lies in the posterior cranial fossa. C. Astrocytoma of the pons is the most common tumor of the brainstem. E. The pons receives its blood supply from the basilar artery.

Question 13

The following statements concern the midbrain:

(a) It passes superiorly between the fixed and free
borders of the tentorium cerebelli.
(b) The oculomotor nerve emerges from the posterior surface below the inferior colliculi.
(c) The superior brachium passes from the superior colliculus to the medial geniculate body.
(d) The cavity of the midbrain is called the cerebral
aqueduct.
(e) The interpeduncular fossa is bounded laterally
by the cerebellar peduncles.

Answer 13

D is correct.

• The cavity of the midbrain is called the cerebral aqueduct (see Fig. 5-28). A. The midbrain passes superiorly through the opening in the tentorium cerebelli posterior to the dorsum sellae. B. The oculomotor nerve emerges from the anterior surface of the midbrain at the level of the superior colliculi (see Fig. 5-25). C. The superior brachium passes from the superior colliculus to the lateral geniculate body and the optic tract and is associated with visual functions (see Fig. 5-23). E. The interpeduncular fossa is bounded laterally by the crus cerebri (see Fig. 5-25).

Question 14

The following statements concern the midbrain:

(a) The oculomotor nucleus is found within it at the level of the inferior colliculus.
(b) The trochlear nerve emerges on the anterior surface of the midbrain and decussates completely in the superior medullary velum.
(c) The trochlear nucleus is situated in the central gray matter at the level of the inferior colliculus.
(d) The lemnisci are situated medial to the central gray matter.
(e) The trigeminal lemniscus lies anterior to the medial lemniscus.

Answer 14

C is correct.

• The trochlear nucleus is situated in the central gray matter of the midbrain at the level of the inferior colliculus (see Fig. 5-25). A. In the midbrain, the oculomotor nucleus is found at the level of the superior colliculus (see Fig. 5-25). B. The trochlear nerve emerges on the posterior surface of the midbrain and decussates completely in the superior medullary velum (see Fig. 5-25). D. The lemnisci are situated lateral to the central gray matter (see Fig. 5-25). E. The trigeminal lemniscus lies posterior to the medial lemniscus (see Fig. 5-25).

Question 15

The following statements concern the colliculi of
the midbrain:

(a) They are located in the tegmentum.
(b) The superior colliculi are concerned with sight reflexes.
(c) The inferior colliculi lie at the level of the oculomotor nerve nuclei.
(d) The inferior colliculi are concernednwith reflexes
of smell.
(e) The superior colliculi lie at the level of the
trochlear nuclei.

Answer 15

B is correct.

• The superior colliculi of the midbrain are concerned with site reflexes. A. The colliculi are located in the tectum (see Fig. 5-25). C. The inferior colliculi lie at the level of the trochlear nerve nuclei (see Fig. 5-25). D. The inferior colliculi are concerned with auditory reflexes. E. The superior colliculi lie at the level of the red nuclei (see Fig. 5-25).

Question 16

The following statements concern the third cranial
nerve nuclei:

(a) The oculomotor nucleus is situated lateral to
the central gray matter.
(b) The sympathetic part of the oculomotor nucleus
is called the Edinger-Westphal nucleus.
(c) The oculomotor nucleus lies posterior to the
cerebral aqueduct.
(d) The nerve fibers from the oculomotor nucleus
pass through the red nucleus.
(e) The oculomotor nucleus lies close to the lateral
longitudinal fasciculus.

Answer 16

D is correct.

• The nerve fibers from the oculomotor nucleus pass through the red nucleus (see Fig. 5-25). A. The oculomotor nucleus is situated in the central gray matter (see Fig. 5-25). B. The parasympathetic part of the oculomotor nucleus is called the Edinger-Westphal nucleus. C. The oculomotor nucleus lies anterior to the cerebral aqueduct (see Fig. 5-25). E. The oculomotor nucleus lies close to the medial longitudinal fasciculus (see Fig. 5-25).

Question 17

A 63-year-old man complaining of difficulty In swallowing, some hoarseness of his voice, and giddiness was seen by a neurologist. All these symptoms started suddenly 4 days previously. On physical examination, he was found to have a loss of the pharyngeal gagging reflex on the left side, left-sided facial analgesia, and left-sided paralysis of the vocal cord.

Based on the clinical history and the results of the physical examination, select the most likely diagnosis.

(a) Meningeal tumor in the posterior cranial fossa
on the right side
(b) Lateral medullary syndrome on the left side
(c) Medial medullary syndrome on the left side
(d) Lateral medullary syndrome on the right side
(e) Medial medullary syndrome on the right side

Answer 17

B is correct.

Question 18

A 7-year-old girl was seen by a neurologist because she complained to her mother that she was seeing double. Careful physical examination revealed that the double vision became worse when she looked toward the left. The patient also had evidence of a mild motor paralysis of her right lower limb without spasticity. There was also a slight facial paralysis involving the whole left side of the face.

Based on the clinical history and the clinical examination, the following neurologic deficits could have been present except:

(a) The double vision caused by weakness of the
left lateral rectus muscle.
(b) The complete left-sided facial paralysis caused
by involvement of the left seventh cranial nerve
nucleus or its nerve.
(c) The mild right hemiparesis produced by damage to the corticospinal tract on the right side.
(d) Magnetic resonance imaging revealed the presence of a tumor of the lower part of the pons on the left side.
(e) The left sixth cranial nerve nucleus was damaged.

Answer 18

C is correct.

• The right-sided hemiparesis was caused
  by damage to the corticospinal tract on the left side of the pons. The corticospinal tract descends through the medulla and crosses to the right side of the midline at the decussation of the pyramids. The patient was later discovered to have a glioma involving the left side of the lower pons.

Question 19

A 42-year-old woman complaining of a severe, persistent headache visited her physician. At first, the headache was not continuous and tended to occur during the night. Now, the headache was present all the time and was felt over the whole head. Recently, she has begun to feel nauseous, and this has resulted in several episodes of vomiting. Last week, on looking in the mirror, she noted that her right pupil looked much larger than the left. Her right upper lid appeared to droop.

The physical examination revealed the following most likely findings except:

(a) Weakness in raising the right eyelid upward
(b) Severe ptosis of the right eye
(c) Obvious dilatation of the right pupil
(d) Ophthalmoscopic examination revealing bilateral papilledema
(e) Evidence of paralysis of either superior oblique
muscle
(f) Examination of the lower limbs revealing mild
spasticity of the left lower limb muscles
(g) Ataxia of the right upper limb
(h) Loss of taste sensation on the posterior third of
the tongue on the left side

Answer 19

H is correct.

• The sensation of taste on the posterior third of the tongue is supplied by the glossopharyngeal nerve, which originates in the medulla oblongata.

Question 20

The combination of the clinical history and the findings in the physical examination enabled the physician to make the following most likely diagnosis.

(a) Tumor involving the left cerebral hemisphere
(b) Tumor Involving the right side of the midbrain
at the level of the superior colliculi
(c) Severe migraine
(d) Cerebral hemorrhage involving the left cerebral
hemisphere
(e) Tumor of the left side of the midbrain

Answer 20

B is correct.

• The combination of raised intracranial pressure (headache, vomiting, and bilateral papilledema), the involvement of the right third cranial nerve (right-sided ptosis, right pupillary dilatation, and right-sided weakness of ocular deviation upward), spasticity of the left leg (right-sided corticospinal tracts), and ataxia of the right upper limb (cerebellar connections on the right side) led the physician to make a tentative diagnosis of an intracranial tumor in the right side of the midbrain at the level of the superior colliculi. An MRI confirmed the diagnosis.

Question 21

The following statements concern the anterior surface of the medulla oblongata:

(a) The pyramids taper inferiorly and give rise to
the decussation of the pyramids.
(b) On each side of the midline, an ovoid swelling called the olive contains the corticospinal
fibers.
(c) The hypoglossal nerve emerges between the
olive and the inferior cerebellar peduncle.
(d) The vagus nerve emerges between the pyramid
and the olive.
(e) The abducens nerve emerges between the pons
and the midbrain.

Answer 21

A is correct.

• The pyramids of the medulla oblongata taper inferiorly and give rise to the decussation of the pyramids (see Fig. 5-9). B. On each side of the midline on the anterior surface of the medulla lateral to the pyramids, an ovoid swelling called the olive contains the olivary nucleus and does not contain the corticospinal fibers. C. The hypoglossal nerve emerges between the pyramid and the olive. D. The vagus nerve emerges between the olive and the inferior cerebellar peduncle. E. The abducens nerve emerges between the pons and the medulla oblongata (see Fig. 5-9).