How do normal eye movements occur?
Six muscles, which control the movement of the eye, are attached to the outside of the wall of the eye. In each eye, there are two muscles that move the eye horizontally. The lateral rectus muscle pulls the eye out towards the ear and the medial rectus muscle pulls the eye in towards the nose. There are four other muscles, which move the eye up or down and at an angle. Each eye muscle receives the command for movement from cranial nerves that exit the brain.