Musculus rectus medialis
Adducts the eye (turns it inward/nasally). Important for convergent gaze.
Origin: Common tendinous ring around the optic foramen
Insertion: Medial sclera of the eyeball
Action: Adducts the eyeball (rotates nasally)
Innervation: Oculomotor nerve (CN III)
Medial strabismus (cross-eyed appearance) can be normal in some Appaloosas or can indicate CN VI paralysis where the lateral rectus is non-functional.
Medial strabismus (cross-eyed appearance) can be normal in some Appaloosas or can indicate CN VI paralysis where the lateral rectus is non-functional. Signs include: Eye turned inward; may be normal breed variation in Appaloosas; if acute onset, suggests CN VI damage from brain disease, EPM, or trauma.
See the Medial Rectus on our interactive 3D horse model. Open 3D Model