Damage to the oculomotor nerve (cranial nerve III) causes which combination of signs?

Damage to the oculomotor nerve (cranial nerve III) causes which combination of signs?

• A. Hearing loss and vertigo.
• B. Tongue deviation.
• C. Ptosis and diplopia from oculomotor nerve palsy.
• D. Facial droop and slurred speech.

Answer: (C)

Damage to the oculomotor nerve disrupts most eye movements, eyelid elevation, and pupil constriction. When these motor functions are lost, the eyelid droops (ptosis) and the eyes cannot coordinate properly, leading to double vision (diplopia). This combination—ptosis with diplopia—is a classic presentation of oculomotor nerve palsy because it reflects the loss of the nerve’s control over multiple extraocular muscles and the levator palpebrae superioris that lifts the eyelid. Depending on the lesion’s extent, the pupil may also dilate due to disrupted parasympathetic fibers. The other options describe signs from different nerves: vestibulocochlear causes hearing loss and vertigo, hypoglossal causes tongue deviation, and facial nerve pathways can cause facial droop and slurred speech.

Damage to the oculomotor nerve disrupts most eye movements, eyelid elevation, and pupil constriction. When these motor functions are lost, the eyelid droops (ptosis) and the eyes cannot coordinate properly, leading to double vision (diplopia). This combination—ptosis with diplopia—is a classic presentation of oculomotor nerve palsy because it reflects the loss of the nerve’s control over multiple extraocular muscles and the levator palpebrae superioris that lifts the eyelid. Depending on the lesion’s extent, the pupil may also dilate due to disrupted parasympathetic fibers. The other options describe signs from different nerves: vestibulocochlear causes hearing loss and vertigo, hypoglossal causes tongue deviation, and facial nerve pathways can cause facial droop and slurred speech.