orbicularis oculi muscle

The orbicularis oculi muscle is a muscle of facial expression, a ring-like muscle functioning in a number of eyelid movements.

Gross anatomy

The orbicularis oculi is subdivided into orbital, palpebral and lacrimal parts.
Each has defined actions.

The orbicularis oculi is secured to the medial and lateral palpebral ligament forming a ring in the eyelid tissue centered about the anterior eye. It also inserts on the eyelid 'skeleton' the tarsal plate. It forms connections between the superficial muscular aponeurotic system (SMAS) of the face and frontalis, the temple and the cheek.

Laterally the fibers are pierced by the zygomaticofacial nerve which supplies the skin over the zygoma.

Orbital part

The orbital part forms the bulk of the muscle, can squeeze the eyelid closed tightly and is used in bright light.

Palpebral part

Has thinner fibers continuous with the orbital part. It functions to lightly close the eyelid.

Lacrimal part

Forms a small slip originating adjacent to the lacrimal gland to insert on the lateral eyelid. It is thought to promote flow within the gland.