[Plate 81, Eyelids]page 51
page 52Eyelids and tears (lacrimal fluid) protect cornea and eyeball from dust and particulate matter.
Eyelids
Two moveable folds of skin that cover the eye anteriorly
Protect the eye from injury and excessive light and keep the corneas moist.
Eyelids separated by an elliptical opening, the palpebral fissure.
Covered by thin skin externally and palpebral conjunctive internally
Palpebral conjunctive continuous with bulbar conjunctive of eyeball
Lines of reflection of palpebral conjunctiva onto eyeball are deep recesses: superior and inferior conjunctival fornices
Strengthened by plates of dense connective tissue: tarsal plates
Tarsal glands embedded in plates
Produce a lipid secretion
a. Lubricates edge of eyelids to prevent then from sticking together
b. Barrier for lacrimal fluid
Medial palpebral ligaments
a. Attach tarsal plates to medial margin of orbit
b. Orbicularis oculi attaches to this ligament
Lateral palpebral ligaments attach tarsal plates to lateral margin of orbit
Orbital septum from tarsal plates to margins of orbit, continuous with periosteum of bony orbit
Skin around the eyes devoid of hair except for eyelashes
Are arranged in double or triple rows on the free edges of the eyelids
Ciliary glands associated with eyelashes: sebaceous glands.
Muscles of the eyelids
Orbicularis oculi
Levator palpebrae superioris
Lacrimal apparatus
Functions
Secretes tears
Prevents desiccation of cornea and conjunctiva
Lubricates eye and eyelid
Antibacterial