The orbicularis oculi is a paired facial muscle surrounding each eye and is part of the circumorbital and palpebral group. It works alongside the corrugator supercilii and levator palpebrae superioris muscles.
Structure
The orbicularis oculi has three parts:
1. Orbital part - Encircles the bony orbit and allows forceful closure of the eye.
2. Palpebral part - Located within the eyelids, enabling gentle closure (e.g., blinking).
3. Deep palpebral (lacrimal) part - Assists in draining tears by compressing the lacrimal sac.
Attachments
• Originates from the frontal bone, maxilla, and lacrimal bone.
• Inserts into the skin around the orbit and lateral palpebral raphe.
Innervation
• Supplied by the facial nerve (cranial nerve VII), specifically its temporal and zygomatic branches.
Function
• Eye closure: Protects and hydrates the eye through blinking.
• Expression: Non-verbal communication (e.g., winking).
• Tear drainage: Aids in tear flow to keep the eye moist.
This muscle plays a vital role in both voluntary and involuntary eye movements.
