[1] The medial rectus muscle is supplied by the inferior division of the oculomotor nerve (III).
[5] Strabismus (lazy eye) may be caused by a medial rectus muscle that is located too high in the orbit of the skull.
[6] Whilst this reduces the ability to abduct and adduct the eye for tracking, it corrects the esotropia and so generally improves vision.
[7] This leaves it vulnerable to being compressed (incarcerated) during skull fractures, which can prevent movement of the eye.
[9] The damage can be minor, such as bruising, or severe, such as cutting through the muscle partially or completely, and nerve injury.