Lacrimal part of orbicularis oculi

The lacrimal part of the orbicularis oculi (Latin: pars lacrimalis musculi orbicularis oculi) is a small muscle lying between the medial palpebral ligament and lacrimal sac. It is one of the orbicularis oculi muscle parts.

The lacrimal part is also known as the deep part of the orbicularis oculi muscle (Latin: pars profounda musculi orbicularis oculi) because it lies most deeply. The orbicularis oculi muscle is classified as the circumorbital and palpebral facial muscle.

Origin

The lacrimal part of the orbicularis oculi originates from the lacrimal bone.

Insertion

This part of the orbicularis oculi muscle inserts into the wall of the lacrimal sac.

Action

Contractions of the lacrimal part of the orbicularis oculi enlarge and widen the lacrimal sac and improve the tear drainage and flow.

Innervation

The lacrimal part of the orbicularis oculi is innervated by the zygomatic branch of the facial nerve (CN VII).

Blood supply

The lacrimal part receives arterial blood supply from the branches of the facial, superficial temporal and ophthalmic arteries.