Double vision (473/1700)

A 62yo male comes to the GP complaining of double vision while climbing downstairs. Which of
the following nerve is most likely involved?
a. Abducens nerve
b. Trochlear nerve
c. Oculomotor nerve
d. Optic nerve
e. Trigeminal nerve































answer: B

Extraocular Muscle Innervations

LR6 SO4 AE3

1.      Lateral Rectus via CN VI (abducens) Double vision occurs when people look toward the side of the affected eye.

2.      Superior Oblique via CN IV (trochlear) The affected eye cannot turn inward and down

3.      All Else via CN III (oculomotor) (superior, medial, and inferior rectus, inferior oblique) The affected eye turns outward when the unaffected eye looks straight ahead, causing double vision. The affected eye can move only to the middle when looking inward and cannot move up and down. Because the 3rd cranial nerve also raises the eyelids and controls the pupils, the eyelid droops, and the pupil may be widened (dilated) and may not narrow (constrict) in response to light.