What is the effect of the superior oblique muscle on eye movement?

The superior oblique muscle is primarily responsible for specific movements of the eye along the vertical and horizontal axes. When activated, it causes the eye to move downwards and towards the nose (inward). This action is due to its anatomical position and the angle at which it attaches to the eye.

When the superior oblique muscle contracts, it not only depresses the eye but also helps to rotate it in such a way that the top of the eye moves towards the nose. Therefore, the correct option reflects that the muscle moves the eye down and inward (not outward as indicated). The confusion may arise in considering the movements as "up and out," which would not be accurate for the function of the superior oblique. The other options do not align with the actual motion facilitated by the superior oblique muscle, which clarifies its primary role in ocular movement.

Understanding this muscle's function is crucial for recognizing how eye alignment and movement are impaired in certain conditions, hence its relevance in medical evaluations and treatments.