The palpebral portion of the orbicularis oculi occupies the eyelids and is responsible for blinking and gentle lid closure. It is functionally distinct from the orbital portion (which produces forceful tight closure). The blink reflex (corneal reflex) is a monosynaptic trigeminal-facial reflex testing the integrity of both CN V and CN VII. The palpebral portion drives the lacrimal pump during blinking.
| Origin | Medial palpebral ligament and adjacent frontal bone; fibres sweep across the upper and lower lids to the lateral canthus |
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| Insertion | Lateral palpebral ligament (lateral raphe); fibres also insert into the skin of the lid margins creating the grey line (the margin between anterior lamella and mucocutaneous junction) |
| Nerve Supply | Temporal branch (upper lid) and zygomatic branch (lower lid) of the facial nerve (CN VII) |
| Blood Supply | Palpebral arteries from the ophthalmic artery (medial palpebral), lacrimal artery (lateral palpebral) |
| Actions | Involuntary blink reflex (protective, high-speed closure mediated by corneal reflex arc via CN V1 afferent and CN VII efferent); voluntary lid closure and gentle lid apposition during sleep; lacrimal pump action by compression of the lacrimal sac during blinking, propelling tears into the nasolacrimal duct |
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Facial palsy (Bell's palsy or surgical injury to CN VII) denervates the palpebral orbicularis, eliminating the blink reflex and protective lid closure. Lagophthalmos (incomplete lid closure) causes exposure keratopathy from corneal desiccation, requiring lubricating drops, moisture chambers, tarsorrhaphy, or gold weight upper lid implants to protect the cornea. In botulinum toxin treatment of blepharospasm (involuntary palpebral orbicularis spasm causing forceful repeated blinking and functional blindness), injection into the palpebral orbicularis reduces hypercontractility while preserving voluntary blinking.
Facial nerve palsy eliminates palpebral orbicularis contraction producing lagophthalmos and absent blink reflex; corneal exposure without adequate lubrication leads to punctate epithelial erosions, stromal ulceration, and vision loss; gold weight upper lid implant (1.2-1.6 g placed in the pre-tarsal plane) uses gravity-assisted lid closure to protect the cornea.
