QuestionSBA
QuestionChoice
The presentation described is consistent with a third nerve palsy - a lesion affecting the oculomotor nerve. When this nerve is affected, there is unopposed movement of the superior oblique (controlled by the trochlear nerve) and the lateral rectus (controlled by the abducens nerve). These two muscles pull the eye down and out respectively.
10001772
a
Oculomotor nerve
QuestionChoice
The trigeminal nerve (fifth cranial nerve) is responsible for the motor and sensory function of the masseter and the temporalis muscles (muscles of mastication). A lesion in the trigeminal nerve would not produce ocular muscle palsies.
10001775
d
Trigeminal nerve
QuestionChoice
The facial nerve (seventh cranial nerve), controls muscles of facial expression and receives sensory information from the anterior 2/3 of the tongue. A lesion in the facial nerve would not result in ocular muscle palsies either.
10001776
e
Facial nerve
QuestionChoice
The abducens nerve (sixth cranial nerve) innervates the lateral rectus, which pulls the eye outwards. A lesion in the abducens nerve would present as an eye that deviates inwards.
10001773
b
Abducens nerve
QuestionChoice
The trochlear nerve (fourth cranial nerve) innervates the superior oblique, which pulls the eye down and inwards. A lesion in the trochlear nerve would result in an eye that is deviated up and out.
10001774
c
Trochlear nerve
Concept
Chapter
2693
3970
Isolated cranial nerve palsies affecting the eye
Topic
141
Neurology
12901
A 73-year-old woman presents to the Emergency Department with an eye that is deviated down and out.

A lesion to which cranial nerve would cause these symptoms?
a