16. Angiography in a 64-year-old woman reveals a laterally expanding lesion with

Question

16. Angiography in a 64-year-old woman reveals a laterally expanding lesion within the cavernous sinus. Further tests confirm that this lesion is an aneurysm of the internal carotid artery. Which of the following is affected first by this expanding lesion owing to its approximation to the internal carotid artery?

a. The maxillary nerve

b. The trochlear nerve

c. The mandibular nerve

d. The oculomotor nerve

e. The abducens nerve

17. A 32-year-old woman becomes acutely ill with fever, pain in the orbits, and diplopia. The neurologist discovers that she has a severe maxillary sinus infection that has spread into her nose and onto the face. The examining physician concludes that this patient has a venous thrombosis. Based on their location and venous connection, which of the following is the most likely venous structure involved in this patient?

a. Straight sinus

b. Transverse sinus

c. Vein of Labbé

d. Cavernous sinus

e. Superior sagittal sinus

18. The caudal end of the spinal cord (conus medullaris) is anchored to the inner aspect of the spinal dural sac by which of the following?

a. Filum terminale externum

b. Filum terminale internum

c. Coccygeal ligament

d. Denticulate ligament

e. Arachnoid trabeculae

A 47-year-old man complains of slowly progressing weakness of both “legs.” On examination he has a flaccid paralysis of both lower extremities, muscle fasciculations, hypotonia, and areflexia. In addition, there is loss of pain and temperature sensations over the anterior aspect of both lower extremities and most of the feet but sparing the little toes.

19. The flaccid paralysis, fasciculations, hypotonia, and areflexia in this patient are most likely the result of damage to what structures?

a. Lateral corticospinal tracts

b. Posterior (dorsal) roots

c. Anterior (ventral) horn cells and alpha motor neurons

d. Reticulospinal/vestibulospinal tracts

e. Afferent fibers involved in monosynaptic reflexes

20. The MRI of a 69-year-old woman reveals a tumor in the posterior fossa resulting in significant compression of the medulla. Which of the following deficits could appear suddenly in this patient and would signal potential medullary failure?

a. Agnosia

b. Paralysis of the lower extremities

c. Complete loss of pain and thermal sense from the body

d. Central apnea

e. Blindness

Explanation / Answer

Ans-16

Cavernous sinus is part of our head which contain following structure in lateral wall of sinus vertically, from superior to inferior:

However nerve listed above, abducence nerve does not run lateral wall of cavernous sinus, rather it runs middle of sinus, alongside of internal carotid artery.

So abducence nerve is affected first due to lesions in cavernous sinus.

So our ( e ) option is correct.

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