Eyelid

The eyelids cover the eyes, with an upper and lower eyelid on each side, and are covered in front with loose skin and behind with adherent conjunctiva. The lower lids possess very little mobility; lids are closed gently by levator palpebrae superioris muscle fibers and forcefully by the orbicularis oculi muscle.

Gross anatomy

The eyelid comprises of a number of key features listed below:

• tarsal plates: eyelids are thickened at the margins to form the tarsal plates, which are formed by dense fibrous tissue
• orbital septum: attached to the anterior lacrimal crest and orbital margins
• medial palpebral ligament: anchors both the tarsal plates to the anterior lacrimal crest
• lateral palpebral ligament: anchors both the tarsal plates to the marginal tubercle (of Whitnall) of the zygomatic bone

Innervation

• upper lid: supplied by supraorbital, supratrochlear, infratrochlear nerves

• lower lid: supplied by the infraorbital nerve