Which nerve is responsible for eye movements downward and inward?

• A. Abducens (CN VI)
• B. Oculomotor (CN III)
• C. Trochlear (CN IV)
• D. Trigeminal (CN V)

Answer: (C)

The movement downward and inward of the eye is produced by the superior oblique muscle, which is innervated by the trochlear nerve. When the eye is adducted (looking toward the nose), the superior oblique pulls the eye downward and also intorts it. This specific action is why the trochlear nerve best fits the question. The other nerves don’t produce this downward-withinward movement on their own: one mainly moves the eye outward, another controls multiple muscles including some that move inward but not in this particular downward-and-inward way, and the trigeminal nerve isn’t involved in eye movements.