third eyelid


Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.

pli·ca sem·i·lu·na·'ris of con·junc·ti·'va

[TA]
1. the semilunar fold formed by the palpebral conjunctiva at the medial angle of the eye;
2. a fold of the conjunctival mucous membrane found in many animals; normally partially hidden in the medial canthus of the eye when at rest, it may be extended to cover part or all of the cornea in a winklike action to clean the cornea, as in birds. Synonym(s): membrana nictitans, nictitating membrane, palpebra III, palpebra tertia, third eyelid

third eyelid

third eyelid


third eyelid eversion
the free margin of the third eyelid is rolled outwards because of a curvature of the cartilage. More prevalent in large breeds of dogs and may be an inherited defect in St. Bernards and German shorthaired pointers.
Enlarge picture
Eversion of the third eyelid in a dog. By permission from McCurnin D, Poffenbarger EM, Small Animal Physical Diagnosis and Clinical Procedures, Saunders, 1991
third eyelid protrusion syndrome
References in periodicals archive ?
The third eyelid gland is attached to the base of the third eyelid where it is not normally visible and it produces approximately 60% of the tear film.
More typically, owners notice the third eyelid when their dog is dreaming, in that middle ground between sound asleep and awake, when her eyes are darting around in dream mode and her eyelids are partially open.
Normally, the third eyelid is held back by the position of the eyeball, so anything that makes the eyeball shrink slightly or sink back into the head will allow the membrane to slip up.
The sites of the dermoids in that study were reported in decreasing order of incidence as the limbus third eyelid canthus eyelid and conjunctiva (Barkyoumb and Leipold 1984).
Microalterations in the third eyelid gland of dogs with keratoconjuntivitis sicca secondary to distemper.
Normally the third eyelid is held back by the position of the eyeball, so anything that makes the eyeball shrink slightly or sink back into the head can make the third eyelid more visible.
The birds can see eight times better than humans, and a transparent third eyelid helps keep their eyes clean and moist.
Hockenhull says: "He had cancer on his third eyelid and it was causing him quite a lot of irritation.
conjunctivitis, keratitis, lacerations of the eyelids, punctured wounds of eyelids, hyphema, sub-conjunctival lower eyelid abscess, bilateral prolapse of third eyelid, nodular conjunctival lesion after lumpy skin disease, foreign body in cornea, perforating corneal wounds and buphthalmos in cattle.
The canine third eyelid (TE) is affected by a number of inflammatory and neoplastic conditions as well as anatomical malformations that may require surgical correction (MARTIN et al.
Mary A: It could be that you are seeing your dog's third eyelid rather than your dog's eye rolling up.
3) Basal cell carcinoma is rare in birds, with documented occurrences in the cervical/ingluvial region of a blue-fronted Amazon parrot (Amazona aestiva), (4) in the beak of a blue and gold macaw (Ara ararauna), (5) and on the leading margin of the third eyelid of a conure (Aratinga species).