Case 179 Answers

Basic Human Neuroanatomy

A Clinically Oriented Atlas

Case 179 Answers

1. Was the involvement in this case intrinsic to or extrinsic to the central nervous system?

Extrinsic

2. List all of the possible structures that could be involved by the pathologic process to produce each of the abnormal signs and symptoms experienced by this patient.

a. Absent smell on the right

Right olfactory nerve (I) or bulb/tract (?? Due to torque on the nerve??)

b. Decreased visual acuity, OD

Right optic nerve (II) (?? Due to torque on the nerve??)

c. Diplopia. Esotropia, OD. Impaired abduction, OD

Right abducent nerve (VI)

d. Hypertropia, OD. Improved diplopia with downward head tilt to the right

Right trochlear nerve (IV)

e. Numbness, tingling, hypalgesia, hypesthesia, hyperpathia, allodynia of right tongue and face

Right trigeminal ganglion, root, or nerve (V)
(all 3 divisions: maxillary and mandibular>ophthalmic)

f. Jaw deviation to the right

Right mandibular division of V

g. Right LMN facial weakness

Right facial nerve (VII)

h. Tinnitus, decreased hearing, AD

Right vestibulocochlear nerve (VIII), right cochlear nuclei

3. Indicate the anatomical location of the pathologic process in this case. Include the side of involvement.

Right middle cranial fossa and upper posterior cranial fossa, involving the right IV, V, VI, VII, and VIII cranial nerves extrinsic to the brain stem.

4. In general, what type of pathologic process do you think is involved in this case? What other differential diagnostic considerations would you entertain?

Neoplastic (vs inflammatory) – Right petrous apex meningioma and operative trauma, + postoperative inflammation

5. What diagnostic procedure(s) would you have undertaken prior to this patient’s surgery?

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