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NEUROANATOMY 3rd > CHAPTER 12 > Flashcards

CHAPTER 12 Flashcards

1
Q
  1. A40-year-old dentist complains of headaches
    and inability to control his walking (gait). His
    physician refers him to a neurologist for further evaluation. The man remembers that 10 years ago he noticed a noise in his right ear that sounded like frying bacon. Neurologic examination reveals the following: loss of hearing on the right side and tinnitus, vertigo and nausea, wide-based ataxic gait with lurching
    to the right side, dysphagia, facial weakness on
    the right side, sensory loss over the face on the
    right side, loss of the corneal reflex on the right
    side, absent gag reflex, and diplopia. The lesion
    site responsible for these neurologic deficits is
    the
    (A) lateral medulla
    (B) medial medulla
    (C) lateral pons
    (D) medial pons
    (E) cerebellopontine (CP) angle
A

1-E. The acoustic neuroma (acoustic schwannoma), which represents 8% of primary intracra-
nial neoplasms, is found in the cerebellopontine (CP) angle. Each of the examination findings is
evidence of a particular condition. The loss of hearing on the right side and the tinnitus indicate
damage to cochlear nerve, the vertigo and nausea indicate damage to the vestibular nerve, the
wide-based ataxic gait with lurching to the right indicates damage to the cerebellum, the dys-
phagia indicates damage to the glossopharyngeal and vagal nerves, the facial weakness on the
right side indicates damage to the facial nerve, the sensory loss over the face on the right side
indicates damage to the spinal trigeminal tract of CN V, the loss of the corneal reflex on the right
side indicates damage to trigeminal (afferent limb) and to facial (efferent limb) nerves, the ab-
sent gag reflex indicates damage to glossopharyngeal (afferent limb) and vagal (efferent limb) nerves, and the diplopia indicates damage to the abducent nerve. A large tumor can damage the pyramidal tract and the abducent nerve. The differential diagnosis should include other tumors of the CP angle (Schwannoma, Arachnoid, Meningioma, Epidermoid; remember SAME).

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2
Q
  1. Tilting the head forward would maximally
    stimulate the hair cells in the
    (A) crista ampullaris of the anterior semicircular duct
    (B) crista ampullaris of the lateral semicircular duct
    (C) crista ampullaris of the posterior semicircular duct
    (D) macula of the utricle
    (E) macula of the saccule
A

2-D. Tilting the head forward would maximally stimulate the hair cells in the utricle. Tilting
the head to the side would maximally stimulate the hair cells in the saccule. The utricle and sac-
cule both respond to linear acceleration and the force of gravity.

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3
Q
  1. A comatose patient’s head is elevated 30°
    from the horizontal. Cold water is injected into
    the left external auditory meatus. If the brain-
    stem is intact, which one of the following ocu-
    lar reflexes would you see?
    (A) Horizontal nystagmus to the left
    (B) Vertical upper nystagmus
    (C) Horizontal nystagmus to the right
    (D) Deviation of the eyes to the left
    (E) Deviation of the eyes to the right
A

3-D. Nystagmus is not seen in comatose patients. In this case, the patient’s eyes will deviate to-
ward the side of cold water injection.

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4
Q
  1. All of the following statements concerning
    decerebrate rigidity are correct EXCEPT
    (A) it results from a lesion transecting the
    brainstem between the superior and inferior colliculi
    (B) it is considered to be alpha rigidity
    (C) it is characterized by opisthotonos with
    arms and legs extended and adducted
    (D) it can be abolished by dorsal root rhizotomy
    (E) it can be abolished by section of the vestibu-
    lar nerve
A

4-B. Classic decerebrate (posturing) rigidity is considered to be gamma rigidity. Alpha rigidity
is seen when the anterior cerebellum of a decerebrate preparation is infarcted.

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5
Q
  1. A patient sitting erect with his head in-
    clined 30° forward is rotated to the right 10
    turns in 20 seconds and then is suddenly
    stopped. All of the following symptoms are ex-
    perienced EXCEPT
    (A) the patient would have a vertical nystagmus
    (B) the fast phase of the nystagmus would be
    to the left
    (C) the slow phase of the nystagmus would be
    to the right
    (D) the patient would past-point to the right
    (E) the patient would experience a sensation
    of turning to the left
A

5-A. The sensation of turning experienced by the patient is called vertigo. This type of nystagmus is called postrotational nystagmus. Stimulation of the hair cells of the posterior ducts results in vertical nystagmus.

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6
Q
  1. All of the following statements concerning
    endolymph are correct EXCEPT
    (A) it is found in the helicotrema
    (B) it is found in the utricle
    (C) it is found in the semicircular ducts
    (D) it is secreted by the stria vascularis
    (E) it is absorbed by the endolymphatic sac
A

6-A. The helicotrema is a space at the apex of the cochlea through which the scala vestibuli and
the scala tympani communicate. The helicotrema contains perilymph.

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7
Q
  1. Which of the following statements concern-
    ing caloric-induced nystagmus is FALSE?
    (A) Cold-water irrigation of the left ear results
    in nystagmus to the right (fast phase)
    (B) Cold-water irrigation of the left ear results in past-pointing to the left
    (C) Caloric testing permits the evaluation of
    the individual semicircular ducts
    (D) Caloric testing is contraindicated in comatose patients
    (E) Hot-water irrigation results in the reverse reactions
A

7-D. One of the advantages of caloric stimulation is that it can be used safely in all states of consciousness. Caloric testing enables the examiner to evaluate the individual semicircular canals separately. Past-pointing and falling are to the side of irrigation. Remember the mnemonic for calorics: COWS = Cold, Opposite, Warm, Same.

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8
Q
  1. Which of the following statements concern-
    ing the semicircular ducts is FALSE?
    (A) They are three in number
    (B) They contain endolymph
    (C) They contain hair cells
    (D) They are found within the vestibule
    (E) They comprise the kinetic labyrinth
A

8-D. The three semicircular (membranous) ducts lie within the three semicircular (osseus)
canals of the petrous part of the temporal bone. They contain endolymph and have hair cells
within the cristae ampullares. The kinetic labyrinth consists of the semicircular ducts; the static labyrinth consists of the utricle and saccule. The vestibule is a central cavity of the inner ear that contains the saccule and the utricle.

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9
Q
  1. All of the following statements concerning
    the hair cells of the vestibular apparatus are
    correct EXCEPT
    (A) hair cells contain one kinocilium and
    many stereocilia (microvilli)
    (B) hair cells of the semicircular ducts are
    stimulated by perilymphatic flow
    (C) hair cells are innervated by bipolar cells
    found in the internal auditory meatus
    (D) hair cells are found in the cristae ampullares
    (E) hair cells are found in the maculae of the
    saccule and utricle
A

9-B. The hair cells of the vestibular apparatus contain one kinocilium and many stereocilia (microvilli). Hair cells of the semicircular ducts are stimulated by endolymphatic flow (not perilymphatic flow); they are innervated by bipolar cells found in the fundus of the internal auditory meatus. Hair cells are found in the cristae ampullares and in the maculae of the utricle and saccule.

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10
Q
  1. All of the following statements concerning
    the static labyrinth are correct EXCEPT
    (A) it responds to linear acceleration
    (B) it responds to the pull of gravity
    (C) it lies within the vestibule of the bony
    labyrinth
    (D) it includes the macula of the utricle
    (E) it is tested clinically by caloric stimulation
A

10-E. The static labyrinth consists of the utricle and saccule, which are found in the vestibule of
the bony labyrinth. The hair cells of the maculae of the utricle and saccule respond to linear acceleration and deceleration and gravitational pull. Introduction of warm or cold water into the external auditory meatus stimulates the hair cells of the semicircular ducts (i.e., kinetic labyrinth).

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11
Q
  1. All of the following statements concerning
    the vestibular ganglion are correct EXCEPT
    (A) it lies within the bony modiolus
    (B) it innervates the hair cells of the cristae
    ampullares
    (C) it innervates the hair cells of the utricle
    and saccule
    (D) it contains bipolar ganglion cells
    (E) it projects directly to the cerebellar cortex
A

11-A. The vestibular ganglion of Scarpa lies in the fundus of the internal auditory meatus. It contains bipolar neurons that innervate the hair cells of the cristae ampullares and the maculae of the utricle and the sacculus. Bipolar neurons project centrally to the vestibular nuclei of the brainstem and the flocculonodular lobe of the cerebellum. The spiral (cochlear) ganglion of the cochlear nerve lies in the modiolus of the petrosal bone.

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12
Q
  1. All of the following statements concerning
    the vestibular nuclei are correct EXCEPT
    (A) they are three in number
    (B) they receive input from the fastigial nuclei
    (C) they project to the medial longitudinal
    fasciculi (MLFs)
    (D) they project to the nuclei of the extraocular muscles
    (E) they are found in the medulla and pons
A

12-A. There are four vestibular nuclei: lateral, medial, inferior, and superior. They receive input from the fastigial nuclei via the uncinate fasciculus and the juxtarestiform body. Vestibulocerebellar fibers project to the nodulus, flocculus, and uvula but not to the fastigial nucleus. They
project via the medial longitudinal fasciculus (MLF) to the ocular motor nuclei (of CN III, CN IV,
and CN VI). Vestibular nuclei are found in the medulla and pons.

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13
Q
  1. All of the following statements concerning
    the lateral vestibulospinal tract are correct
    EXCEPT
    (A) it arises from the lateral vestibular nucleus
    (B) it is located in the ventral funiculus of the
    spinal cord
    (C) it is found at all spinal cord levels
    (D) it facilitates extensor muscle tone in antigravity muscles
    (E) it is a crossed pathway
A

13-E. The lateral vestibulospinal tract arises from the ipsilateral lateral vestibular nucleus of Deiters, located in the lateral pontine tegmentum, and descends to all spinal cord levels in the ventral funiculus. It facilitates extensor muscle tone in the antigravity muscles. It is an uncrossed tract.

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14
Q
  1. All of the following statements concerning
    the medial longitudinal fasciculus (MLF) are
    correct EXCEPT
    (A) it is located in the midbrain
    (B) it is located in the spinal cord
    (C) it contains vestibulo-oculomotor fibers
    (D) it mediates adduction in lateral conjugate
    gaze on command
    (E) transection results in paralysis of conver-
    gence
A

14-E. Transection of the medial longitudinal fasciculus (MLF) results in a medial rectus palsy
on attempted lateral gaze; convergence remains intact. The MLF extends from the spinal cord to
the rostral midbrain; it contains vestibulo-oculomotor fibers that mediate eye movements in response to head and neck posture. It carries fibers to the medial rectus subnucleus from the pontine lateral conjugate gaze center.

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15
Q
  1. All of the following statements concerning
    vestibular nystagmus are correct EXCEPT
    (A) it is named after the fast component
    (B) it has a slow component that is opposite
    the direction of rotation
    (C) it may be horizontal, vertical, or rotatory
    (D) it is frequently associated with nausea
    and vertigo
    (E) it results in nystagmus to the same side
    with ice-water irrigation of the external
    auditory meatus
A 
15-E. Nystagmus is named after the fast component; the slow component is opposite the direction of rotation, thus maintaining visual fixation. Nystagmus may be horizontal, vertical, or rotatory and is frequently associated with nausea, vomiting, and vertigo. Irrigation of the external
 auditory meatus (with the head tilted back 60°) with ice water results in nystagmus to the opposite side. Remember the mnemonic COWS = Cold, Opposite, Warm, Same.
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16
Q
  1. All of the following statements concerning
    the primary vestibular cortex are correct EXCEPT

(A) it receives input from the ventral posteroinferior (VPI) nucleus
(B) it receives input from the ventral postero-
lateral (VPL) nucleus
(C) it is located in areas 2 and 3
(D) it is located in the somesthetic cortex
(E) it is located in the paracentral lobule

A

16-E. The primary vestibular cortex (areas 2v and 3a) is located in the postcentral gyrus, the
somesthetic cortex of the parietal lobe. The vestibular cortex receives input from the ventral posteroinferior (VPI), ventral posterolateral (VPL), and the ventral lateral nuclei of the thalamus. The paracentral lobule is a continuation of the motor and sensory strips onto the medial surface of the hemisphere; it receives no vestibular input.

17
Q
  1. Causes the symptoms of cranial nerves
    (CNs) V, VII, and VIII

The response options for items 17-21 are the
same. You will be required to select one answer
for each item in the set.

(A) Meniere disease
(B) Benign positional vertigo
(C) Acoustic schwannoma
(D) Medial longitudinal fasciculus (MLF) syndrome
(E) Multiple sclerosis

Match each characteristic with the condition it

A

17-C. The acoustic schwannoma, which is found in the cerebellopontine (CP) angle of the posterior cranial fossa, impinges on CNs V, VII, and VIII. CN V lesions result in loss of pain and temperature sensation on the ipsilateral face and loss of the corneal reflex; CN VII lesions result in a lower motor neuron paralysis of the ipsilateral muscles of facial expression and loss of the
corneal reflex; and CN VIII lesions result in loss of hearing, nystagmus, tinnitus, nausea, vertigo, and vomiting. (See Chapter 13, Cranial Nerves.)

18
Q
  1. Is an inner ear disease associated with in-
    creased endolymphatic fluid pressure

The response options for items 17-21 are the
same. You will be required to select one answer
for each item in the set.

(A) Meniere disease
(B) Benign positional vertigo
(C) Acoustic schwannoma
(D) Medial longitudinal fasciculus (MLF) syndrome
(E) Multiple sclerosis

Match each characteristic with the condition it

A

18-A. Meniere disease (labyrinthine vertigo) is the most common cause of true vertigo. It is characterized by abrupt attacks of vertigo, nystagmus, nausea and vomiting, tinnitus, fullness in the ear, and hearing loss. This disease is caused by a distention of the endolymphatic system (labyrinthine hydrops). Drugs used to treat motion sickness may be helpful. Destruction (decompression) of the vestibule and an endolymphatic-subarachnoid shunt have proved useful.

19
Q
  1. Is the most common cause of internuclear
    ophthalmoplegia (INO)

The response options for items 17-21 are the
same. You will be required to select one answer
for each item in the set.

(A) Meniere disease
(B) Benign positional vertigo
(C) Acoustic schwannoma
(D) Medial longitudinal fasciculus (MLF) syndrome
(E) Multiple sclerosis

Match each characteristic with the condition it

A

19-E. The most common cause of internuclear ophthalmoplegia is multiple sclerosis. Other
causes of INO are vascular insults and intraparenchymal tumors (pontine gliomas). Multiple sclerosis, a demyelinating disease of the central nervous system is characterized by the following deficits: Ocular signs (retrobulbar neuritis and INO); brainstem and cerebellar signs (deafness,vertigo, ataxia, and intention tremor); pyramidal tract signs (spastic paresis with Babinski sign); sensory disturbances (paresthesias or dysesthesias); and bladder and rectal incontinence.

20
Q
  1. Results in cuprolithiasis of the posterior
    semicircular duct

The response options for items 17-21 are the
same. You will be required to select one answer
for each item in the set.

(A) Meniere disease
(B) Benign positional vertigo
(C) Acoustic schwannoma
(D) Medial longitudinal fasciculus (MLF) syndrome
(E) Multiple sclerosis

Match each characteristic with the condition it

A

20-B. Benign positional vertigo, which is more common than Meniere disease, is characterized
by paroxysmal vertigo, oscillopsia, and nystagmus. It occurs as the result of assumption of certain positions of the head (i.e., lying down or rolling over in bed). Such vertigo is due to cuprolithiasis of the posterior semicircular duct— a dislocation of the otoliths that move freely with movement of the head. The following procedure is diagnostic. The patient is moved from a sitting to a recumbent position (on an examination table), and the head is tilted 30° down over the edge of the table, then 30° to one side, and then 30° to the other side. The patient has a paroxysm of vertigo (Hallpike
maneuver).

21
Q
  1. Consists of lateral gaze palsy and monocular nystagmus

The response options for items 17-21 are the
same. You will be required to select one answer
for each item in the set.

(A) Meniere disease
(B) Benign positional vertigo
(C) Acoustic schwannoma
(D) Medial longitudinal fasciculus (MLF) syndrome
(E) Multiple sclerosis

Match each characteristic with the condition it

A

21-D. Medial longitudinal fasciculus (MLF) syndrome [internuclear ophthalmoplegia (INO)]
consists of a medial rectus palsy on attempted lateral gaze. Nystagmus in the abducting eye is
evident. Convergence is intact. This syndrome is seen frequently in multiple sclerosis.

NEUROANATOMY 3rd (29 decks)

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