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 muscle 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 centred 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 muscle, the temple and the cheek. 

Laterally the fibres 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

HasThe palpebral part of the muscle has thinner fibres continuous with the orbital part. It functions to lightly close the eyelid. 

Lacrimal part

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