The Caninus muscle (also known as levator anguli oris) originates in the upper jaw bone area  near the canine and inserts near the corner of the mouth in tissues of the other muscles there (e.g., o. oris). It pulls the corner of the lip up in an almost vertical direction, sharply angling the lip corners up in a kind of "smile."

Caninus is innervated by the zygomatic and buccal branches of the facial nerve (VII) and is supplied with blood by the facial artery.