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Neuroanatomy - Cranial Nerve Pathologies

Q. A 65 y/o man was in a meeting when suddenly he lost control of the right side of his body, including his face. He slumped in his chair and the right side of his face appeared to sag and he complained of double vision. He did not lose consciousness. Somatosensation is intact. Movement and strength on the left side of his body are normal. He is able to sit assisted in a chair with arm and back support. (a) He is able to voluntarily move his right upper limb at the shoulder and his right lower limb at the hip but strength is less than half on the left side. He cannot move any other joints in his limbs on the right.

Questions:

All cranial nerves are intact except for _____________ .

(a) Where is the lesion? (area of CNS and side)
(b) He is unable to voluntarily move his right lower face.
(c) He cannot move his left eye medially, downward or upward.
(d) He cannot fully open his left eye.
(e) The left eye pupil is dilated and does not contract in response to light shined into the eye.

Solution Preview

FROM THE ORIGINAL POSTER:

These are the answers I have come up with, could you please check them?

(a) Lesion is " Left Corticospinal tract"
(b) Facial nerve - buccinators
(c) Abducens nucleus (medial strabismis)
(d) Trochlear
(e) Occulomotor nerve

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OTA's RESPONSE TO THE ANSWERS:

(a) Lesion is " Left Corticospinal tract"
Yes, but more than just the corticospinal tract is affected.

(b) Facial nerve - buccinators
Yes.

(c) Abducens nucleus (medial strabismis)
You got this backwards -- the abducens nerve innervates the lateral rectus, which moves the eye laterally. The patient can still move his left eye laterally.

(d) Trochlear
The trochelar nerve controls the eyeball itself. Not being able to open your eye indicates a problem with the eyelid, not the eyeball. There is a lesion affecting the oculomotor nerve.

(e) Occulomotor nerve
Yes.

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Q. A 65 y/o man was in a meeting when suddenly he lost control of the right side of his body, including his face. He slumped in his chair and the right side of his ...

Solution Summary

This posting consists of a description of various neurological symptoms. The solution uses these symptoms to localize the lesion, explain which cranial nerves are affected, and explain the symptoms that are present (listed as b through e).

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