Plica semilunaris of conjunctiva

Plica semilunaris of conjunctiva

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Plica semilunaris of conjunctiva

The Plica semilunaris of conjunctiva is a small, crescent-shaped fold of conjunctiva located at the inner corner of the human eye. It is a vestigial remnant of the nictitating membrane (the "third eyelid") which is present in other animals.

Anatomy

The plica semilunaris is located in the medial canthus of the eye. It is a fold of bulbar conjunctiva, the thin, transparent tissue that covers the inner surface of the eyelid and the white part of the eyeball. The plica semilunaris is highly vascular and contains a large number of goblet cells, which produce mucus to keep the eye moist.

Function

The primary function of the plica semilunaris is to facilitate eye movement. It allows for greater rotation of the globe, particularly in the horizontal direction. It also aids in the drainage of tears by directing them towards the lacrimal caruncle, the small, pink, globular nodule at the inner corner of the eye.

Clinical significance

In some cases, the plica semilunaris may become inflamed or infected, a condition known as plica syndrome. This can cause symptoms such as redness, swelling, and discomfort. Treatment typically involves the use of topical antibiotics or anti-inflammatory drugs.

See also

• Conjunctiva
• Nictitating membrane
• Human eye