Chapter 9 : Brainstem (4)

Question 1

1. A 40-year-old female librarian is brought to the emergency department. Neurologic examination reveals the following: blood pressure 160/90 mm Hg, numbness on the right side of her lower face, no weakness in upper or lower extremities, tongue deviating to right side on protrusion, uvula deviating 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

Answer 1

1–B. A lesion of the genu of the internal capsule 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 uvula deviates to the intact side when the patient says ah. The muscles of the uvula and palatal arches are innervated by the vagal nerve (CN X).

Question 2

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

Answer 2

2–C. The cerebral aqueduct is found in the mesen cephalon; it connects the third ventricle to the fourth ventricle.

Question 3

The response options for items 3 to 10 are the same. Select one answer for each item in the set.
(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
Match the following structures with the appropriate
brainstem division.

3. Decussation of the superior cerebellar peduncle

Answer 3

3–B. The decussation of the superior cerebellar peduncle is diagnostic of midbrain division at the
level of the inferior colliculus

Question 4

The response options for items 3 to 10 are the same. Select one answer for each item in the set.
(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
Match the following structures with the appropriate
brainstem division.

4. Inferior olivary nucleus

Answer 4

4–E. The inferior olivary nucleus, a cerebellar relay nucleus, is the most prominent nucleus in the
lateral medulla.

Question 5

The response options for items 3 to 10 are the same. Select one answer for each item in the set.
(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
Match the following structures with the appropriate
brainstem division.

5. Nucleus ambiguus

Answer 5

5–E. The nucleus ambiguus is found in the lateral medulla; it gives rise to the SVE components
of cranial nerves IX, X, and XI.

Question 6

The response options for items 3 to 10 are the same. Select one answer for each item in the set.
(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
Match the following structures with the appropriate
brainstem division.

6. Abducent nucleus

Answer 6

6–C. The abducent nucleus (CN VI) is located in the dorsomedial tegmentum of the pons. All
brainstem cranial nerve nuclei are found in the tegmentum

Question 7

The response options for items 3 to 10 are the same. Select one answer for each item in the set.
(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
Match the following structures with the appropriate
brainstem division.

7. Facial nucleus

Answer 7

7–C. The facial nucleus (CN VII) is located in the lateral tegmentum of the pons.

Question 8

The response options for items 3 to 10 are the same. Select one answer for each item in the set.
(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
Match the following structures with the appropriate
brainstem division.

8. Oculomotor nucleus

Answer 8

8–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

Question 9

The response options for items 3 to 10 are the same. Select one answer for each item in the set.
(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
Match the following structures with the appropriate
brainstem division.

9. Red nucleus

Answer 9

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

Question 10

The response options for items 3 to 10 are the same. Select one answer for each item in the set.
(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
Match the following structures with the appropriate
brainstem division.

10. Trochlear nucleus

Answer 10

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