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Flashcards in BRAINSTEM Deck (16)
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1. A 40 year old female librarian is brought to the emergency department. Neurological examination reveals the following; blood pressure 160/90 mm of Hg, numbness on the right side of her lower face. No weakness in upper or lower extremities, tongue deviates to right side on protrusion, uvula deviates to the left side when patient says “Ah”, The lesion causing these symptoms is found in which of the following loci?
A. Anterior limb of internal capsule
B. Genu of internal capsule, left side
C. Claustrum
D. Paracentral lobule, right side
E. Posterior limb internal capsule

1-B A lesion of the genu of the internal eapsule destroys corticobulbar fibers. The facial nucleus receives bilateral corticobulbar input, the upper face division receives bilateral input, and the lower face division receives only contralateral input. The hypoglossal nucleus receives only contralateral corticobulbar input. When the tongue is protruded, it deviates to the weak side due to the unopposed activity of the intact genioglossus muscle. The ucula deviates to the intact side when the patient says “Ah” the muscles of the uvula and palatal arches are innerverted by the vagal nerve (CN X)

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2. The cerebral aqueduct is found in which part of the brain?
A. Telencephalon D. Metencephalon
B. Diencephalon E. Myelencephalon
C. Mesencephalon

2-C The cerebral aqueduct is found in the mesencephalon; in connects the third ventricle to the fourth ventricle

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3. All of the following statements concerning the trapezoid body are correct EXCEPT
A. it is found in the ventral pontine tegmentum
B. it contains the medial longitudinal faseiculus (MLF)
C. it contains the medial lemniscus
D. it contains aberrant corticubulbar fibers
E. it contains auditory fibers

3-B The trapezoid body contains auditory fibers from the cochlear andsuperior olivary nuclei, the medial lemniscus, and corticobulbar fibers. Exiting intra axial abducent fibers pass through the trapezoid body. The medial longitudinal fasculus (MLF) lies dorsal to this strukture.

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4. All of the following statements concerning the medulla oblongata are correct EXCEPT
A. it exteds from the pyramidal dcussation to the inferior pontine sulcus
B. it contains the facial nucleus
C. it contains the medial and inferior vestibular nuclei
D. it contains the inferior olivary nucleus
E. It contains the nucleus ambiguous

4-B On its ventral aspect, the medulla extends from the pyramidal decussation to the inferior pontine sulcus (pontobulbar sulcus); on its dorsal aspect, it extends from the pyramidal decussation to the striae medullares of the rhomboid fossa. The medial and inferior vestibular nuclei are found in the medulla and extend into the caudal pontine tegmentum. The inferior olivary nucleus, a cerebellar relay nucleus, is the most prominent nucleus of the medulla. The nucleus ambiguous is found in the medulla; it gives rise to special visceral efferent (SVE) fibres of CN IX, CN X and CN XI. The facial nucleus is found in the caudal pontine tegmentum.

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5. All of the following statements concerning the hypoglossal nucleus are correct EXCEPT
A. it gives rise to special visceral efferent (SVE) fibers
B. it has axons that exit the medulla between the olive and the pyramid
C. it lies dorsal to the medial longitudinal fasciculus (MLF)
D. it innervates the intrinsic musculature of the tongue
E. its intra-axial root fibers lie adjacent to the medial lemniscus

5-A The hypoglossal nucleus of CN XII gives rise to general somatic effenrent (GSE) fibers. The hypoglossal nucleus lies dorsal to the medial longitudinal fasciculus (MLF), gives rise to fibers that exit the medulla in the preolivary suleus, and innervates the intrinsic and extrinsic muscles of the tongue (except the paloglossus muscle, which is innervated by CN X). intra axial root fibers lie between the medial lemniscus and the inferior olivary nucleus.

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6. All of the following statements concerning the motor nucleus of the trigeminal nerve are correct EXCEPT
A. it plays a role in the corneal reflex
B. it lies medial to the principal sensory nucleus of CN V
C. it is located in the rostral pontine tegmentum
D. it receives bilateral input from corticobulbar fibers
E. it gives rise to special visceral efferent (SVE) fibers

6-A The motor nucleus of the trigeminal nerve (CN V) is a component of the special visceral efferent (SVE) cell column, lies medial to the principal sensory nucleus of CN V, is found in the rostral pontine tegmentum, and receives bilateral corticobulbar input. The afferent limb of the facial nerve (CN VII), which innervates the orbicularis oculi muscle.

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7. All of the following statements concerning the trochlear nerve are correct EXCEPT
A. it has its nucleus in the midbrain tegmentum
B. it exits the brainstem caudal to the inferior colliculus
C. it decussates in the superior medullary velum
D. it innervates a muscle that depresses the globe
E. it innervates a muscle that extorts the globe

7-E The trochlear nerve (CN IV) has its nucleus in the midbrain tegmentum at the level of the inferior colliculus. It decussates in the superior medullary velum and exits the brainstem lateral to the frenulum of the superior medullary velum. It is the only cranial nerve to exit the brainstem from the dorsal surface. It innervates the superior oblique muscle, which depresses, intorts, and abducts the eyeball.

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8. All of the following statements concerning the oculomotor nuclear complex are correct EXCEPT
A. stimulation of its parasympathetic components results in mydriasis
B. demage to its general somatic efferents (GSE) fibers results in severe ptosis
C. it is found in the midbrain at the level of the superior colliculus
D. its preganglionic parasympathetic fibers synapse in the ciliary ganglion
E. its exiting GSE fibers pass through the crus cerebri

8-A Stimulation of the parasympathetic component resultsi n miosis (sphineter pupillae muscle). Preganglionic parasympathetic fibers synapse in the ciliary ganglion. The oculomotor nuclear complex is found in the midbrain at the level of the red nucleus and the superior colliculus. Exiting oculomotor fibers pass through the crus cerebri. Transection of these fibers results in severe ptosis, a dilated pupil paralysis of the medial, superior, and inferior and inferior recti muscles and paralysis of the inferior oblique and the levator palpebrae muscles. The paralystic eye “looks down and out.”

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A. Midbrain, at level of superior colliculus
B. Midbrain, at level of inferior colliculus
C. Tegmentum of pons
D. Base of pons
E. Lateral medulla
F. Medial medulla

9. Decussation of the superior cerebellar peduncler

9-B The decussation of the superior cerebellar peduncle is diagnostic of midbrain division at the level of the inferior colliculus

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A. Midbrain, at level of superior colliculus
B. Midbrain, at level of inferior colliculus
C. Tegmentum of pons
D. Base of pons
E. Lateral medulla
F. Medial medulla

10. Inferior olivary nucleus

10-E The inferior olivary nucleus, a cerebellar relay nucleus, is the most prominent nucleus in the lateral medulla

11

A. Midbrain, at level of superior colliculus
B. Midbrain, at level of inferior colliculus
C. Tegmentum of pons
D. Base of pons
E. Lateral medulla
F. Medial medulla

11. Nucleus ambiguous

11-E The nucleus ambiguous is found in the lateral medulla; it gives rise to the special visceral efferent (SVE) components of cranial nerves IX, X and XI

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A. Midbrain, at level of superior colliculus
B. Midbrain, at level of inferior colliculus
C. Tegmentum of pons
D. Base of pons
E. Lateral medulla
F. Medial medulla

12. Abducent nucleus

12-C The abducent nucleus (CN VI) is located in the dorsomedial tegmentum of the pons. All brainstem eranial nerve nuclei are found in the tegmentum.

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A. Midbrain, at level of superior colliculus
B. Midbrain, at level of inferior colliculus
C. Tegmentum of pons
D. Base of pons
E. Lateral medulla
F. Medial medulla

13. Facial nucleus

13-C The facial nucleus (CN VII) is located in the lateral tegmentum of the pons

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A. Midbrain, at level of superior colliculus
B. Midbrain, at level of inferior colliculus
C. Tegmentum of pons
D. Base of pons
E. Lateral medulla
F. Medial medulla

14. Oculomotor nucleus

14-A The oculomotor nucleus (CN III) lies in the dorsomedial tegmentum of the midbrain at the level of the superior colliculus; it lies medial to the medial longitudinal fasciculus

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A. Midbrain, at level of superior colliculus
B. Midbrain, at level of inferior colliculus
C. Tegmentum of pons
D. Base of pons
E. Lateral medulla
F. Medial medulla

15. Red nucleus

15-A The red nucleus is diagnostic of midbrain division at the superior colliculus; it lies between the oculomotor nucleus (CN III) and the substantia nigra

16

A. Midbrain, at level of superior colliculus
B. Midbrain, at level of inferior colliculus
C. Tegmentum of pons
D. Base of pons
E. Lateral medulla
F. Medial medulla

16. Trochlear nucleus

16-B The trochlear nerve (CN IV) is located in the dorsomedial tegmentum of the midbrain at the level of the inferior colliculus.