Musculus caninus
Small muscle elevating the upper lip corner. Named for its prominence in canines; assists with lip manipulation and facial expression in horses.
Origin: Maxilla, ventral to the infraorbital foramen
Insertion: Upper lip near the commissure
Action: Elevates and retracts the upper lip laterally
Innervation: Dorsal buccal branch of facial nerve (CN VII)
Regional nerve blocks for dental procedures temporarily affect this muscle due to proximity of the infraorbital foramen.
Regional nerve blocks for dental procedures temporarily affect this muscle due to proximity of the infraorbital foramen. Signs include: Temporary lip droop following dental work; difficulty eating for a few hours post-procedure; asymmetric lip position that resolves.
See the Caninus on our interactive 3D horse model. Open 3D Model