- A winglike triangular membrane. Although a pterygium can be anywhere, including behind the knee, it commonly refers to a winglet of the conjunctiva. This pterygium may extend across the white of the eye toward the inner corner of the eye. It is caused by prolonged exposure of the eyes to wind and weather, or can be an inherited disorder caused by a single gene.
* * *1. A triangular patch of hypertrophied bulbar subconjunctival tissue, extending from the medial canthus to the border of the cornea or beyond, with apex pointing toward the pupil. SYN: web eye. 2. Forward growth of the cuticle over the nail plate, seen most commonly in lichen planus. SYN: p. unguis. 3. An abnormal skin web. [G. pterygion, anything like a wing, a disease of the eye, dim. of pteryx, wing]- p. colli a congenital, usually bilateral, web or tight band of skin of the neck extending from the acromion to the mastoid seen in Turner's syndrome and Noonan syndrome.
* * *1) a triangular fleshy mass of thickened conjunctiva occurring usu. at the inner side of the eyeball, covering part of the cornea, and causing a disturbance of vision2) a forward growth of the cuticle over the nail
* * *n.a triangular overgrowth of the cornea, usually the inner side, by thickened and degenerative conjunctiva. It is most commonly seen in people from dry hot dusty climates, and only rarely interferes with vision.
* * *pte·ryg·i·um (tə-rijґe-əm) pl. pteryґgia [Gr. pterygion wing] 1. a winglike structure. 2. especially, an abnormal triangular fold of membrane in the interpalpebral fissure, extending from the conjunctiva to the cornea; it is immovably united to the cornea at its apex, firmly attached to the sclera in its middle portion, and merged with the conjunctiva at its base.
Pterygia of both the lateral and medial canthi.
Medical dictionary. 2011.