Which muscle's primary function is to move the eye upward?

The muscle responsible for moving the eye upward is the Superior Rectus. This muscle is one of the extraocular muscles that control eye movement and is primarily involved in elevating the eyeball. The Superior Rectus originates from the common tendinous ring at the back of the orbit and inserts into the superior part of the eyeball. When the Superior Rectus contracts, it pulls the eye upward, allowing for movements such as looking up towards the ceiling.

Understanding its function is crucial for optometric technicians, as the proper movement of the eyes is essential for visual tracking and depth perception. The other muscles mentioned in the options have different primary functions: the Inferior Rectus moves the eye downward, the Inferior Oblique assists in elevating the eye but also contributes to outward rolling, and the Medial Rectus primarily controls the inward movement of the eye towards the nose.