Neuroanatomy

Question 1

2. All of the following statements are correct regarding the medial lemniscus EXCEPT:
   A. Near the sensory decussation, its blood supply comes from the anterior spinal artery.
   B. The medial lemniscus can be found in close proximity to the anterolateral tract in the medulla. Its somatotopy in the pons is such that leg fibers are
   lateral to arm fibers.
   C. The fibers of the medial lemniscus arise from the cuneate and gracile nuclei.
   D. Brainstem lesions involving medial lemniscus fibers usually include adjacent
   structures, resulting in motor and sensory losses.
   E. None of the above statements are correct.

Answer 1

2.B. The medial lemniscus (ML) is widely separated from the anterolateral system
(ALS) in the medulla. In fact, ML and ALS fi bers receive diff erent blood supplies
in the medulla. In the midbrain and pons, the ML and ALS are in close proximity
and receive similar blood supplies.

Question 2

4. Which of the following lines at the craniocervical junction extends from the basion to the opisthion?
A. McRae’s line
B. McGregor’s line
C. Chamberlain’s line
D. Wackenheim’s line
E. Anterior marginal line

Answer 2

4.A. McRae’s line is from the basion to the opisthion.

Question 3

5. The somatotopic arrangement in the ventral horn is such that the
   A. flexors are dorsal to extensors and limbs are medial to trunk.
   B. extensors are dorsal to fl exors and limbs are medial to trunk.
   C. flexors are dorsal to extensors and limbs are lateral to trunk.
   D. extensors are dorsal to fl exors and limbs are lateral to trunk.
   E. None of the above

Answer 3

5.C. It is helpful to remember that this pattern of somatotopy can be appreciated in
the descending motor pathways: those that are concerned with fl exor musculature (corticospinal tract and rubrospinal tract) lie dorsal to those tracts concerned with extensor musculature.

Question 4

8. Somatic motor eff erents to the urethral sphincter are located in
   A. intermediolateral cell columns of the sacral cord.
   B. Onuf’s nucleus.
   C. Barrington’s nucleus.
   D. All of the above
   E. None of the above

Answer 4

8.B. Somatic motor eff erents to the sphincter are located in the ventral lateral area
of Onuf’s nucleus. Sacral parasympathetics to the bladder are located in intermediolateral cell columns of the sacral cord. Barrington’s nucleus is also
known as the pontine micturition center and is responsible for initiating the
process of micturition.

Question 5

10. Regarding the anatomy near the cavernous sinus, the borders of the clinoidal
triangle are cranial nerves
A. I and II.
B. II and III.
C. III and IV.
D. IV and V.
E. None of the above

Answer 5

10.B. The clinoidal triangle is defined by the medial border of the optic nerve medially and the oculomotor nerve laterally

Question 6

14. Which of the following statements is most accurate regarding the nerve supplying the teres minor muscle?
    A. It has a contribution from the lateral cord.
    B. It is an extension of the posterior cord.
    C. Ventral rami C8 and T1 are major contributors to this nerve.
    D. It is derived from the same cord as the musculocutaneous nerve.
    E. None of the above

Answer 6

14.B. The posterior cord gives rise to the axillary nerve and the radial nerve as its
terminal branches.

Question 7

15. The pterion is formed by the junction of the all of the following EXCEPT:
A. Frontal bone
B. Sphenoid bone
C. Zygomatic bone
D. Temporal bone
E. Parietal bone

Answer 7

15.C. The pterion is located about two fi ngerbreadths above the zygomatic arch, and
a thumb’s breadth behind the frontal process of the zygomatic bone; however,
the zygomatic bone does not form the pterion.

Question 8

18. Which of the following is incorrect regarding the zona incerta?

A. It is a zone of gray matter between the thalamic and lenticular fasciculi.
B. It is composed of cells that are continuous laterally with the thalamic reticular nucleus.
C. Unlike the thalamic reticular nucleus, the neurons of this zone do not display immunoreactivity for the calcium binding protein calbindin D-28k.
D. It receives corticofugal fi bers from the precentral cortex.
E. All of the above statements are correct.

Answer 8

18.C. The zona incerta is a zone of gray matter between the thalamic and lenticular fasciculi. It is composed of cells that are continuous laterally with the thalamic reticular nucleus. Unlike the thalamic reticular nucleus, the neurons of this zone display immunoreactivity for the calcium binding protein calbindin
D-28k. It receives corticofugal fibers from the precentral cortex.

Question 9

20. The anterior loop of the internal carotid artery lies in the floor of this triangle.
A. Lateral triangle
B. Anterior lateral triangle
C. Parkinson’s triangle
D. Anterior medial triangle
E. None of the above

Answer 9

20.D - carotid triangle ??