What is the primary function of the medial rectus muscle?

The primary function of the medial rectus muscle is to rotate the eye inward toward the nose, which is known as adduction of the eye. This muscle is one of the extraocular muscles responsible for controlling eye movements. When the medial rectus contracts, it pulls the eye toward the midline, allowing for movements such as looking at objects closer to the face. Understanding the role of the medial rectus is essential for grasping how coordinated eye movements occur and how each extraocular muscle contributes to the overall functioning of vision and eye alignment.