The Probert Encyclopaedia of Medicine

ORBICULARIS OCULI

The orbicularis oculi (sphincter oculi; orbicularis palpebrarum) muscle is a broad, thin, ring shaped layer of muscle that covers the eyelid and the surrounding orbit. Because of its shape it is classified as a sphincter muscle. The muscle is composed of three parts: the palpebral portion, the orbital portion, and the lachrimal portion. The palpebral portion covers the eyelid. It originates from the palpebral ligament, passes over each eyelid and inserts in the palpebral raphe. The orbital portion of the muscle surrounds the orbit, extending from the bottom of the forehead down to the front of the cheek. It originates from the frontal process of the maxilla (upper jaw), encircles the orbit, and inserts near its point of origin. The upper fibres of the orbital portion blend with the occipito- frontalis and corrugator supercilli. The lachrimal portion (tensor tarsi; Horner's muscle; Duverney's muscle) originates from the lachrimal crest inside of the bridge of the nose and passes across the lachrimal sac to insert with the palpebral portion of the muscle. This muscle is innervated by the facial nerve and supplied by the angular artery and branches of the temporal artery. The three portions work together to narrow the eye, thus causing the eye to close or blink.
Research Orbicularis Oculi