| third eyelid | The semilunar fold formed by the palpebral conjunctiva at the medial angle of the eye, 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 winking-like action to clean the cornea, as in birds. Synonym: membrana nictitans, nictitating membrane, palpebra III, palpebra tertia, third eyelid. Synonym: plica lunata, plica semilunaris of eye, semilunar conjunctival fold. (05 Mar 2000) |
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| arterial arch of lower eyelid | Formed by the medial palpebral artery which communicates with a branch of the lacrimal artery along the tarsal margin. Synonym: arcus palpebralis inferior. (05 Mar 2000) |
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| arterial arch of upper eyelid | Formed by communicating branches of the medial and lateral palpebral arteries. Often two arches are present, one located near the free border of the tarsal plate, the other along the upper border of the tarsus. Synonym: arcus palpebralis superior. (05 Mar 2000) |
| veins of inferior eyelid | Veins of inferior eyelid; veins originatin gin the inferior eyelid and emptying into the angular vein. Synonym: venae palpebrales inferiores, veins of inferior eyelid. (05 Mar 2000) |
| veins of superior eyelid | Veins draining the superior eyelid anteriorly into the angular vein. Synonym: venae palpebrales superiores, veins of superior eyelid. (05 Mar 2000) |
| conditioning, eyelid | Reflex closure of the eyelid occurring as a result of classical conditioning. (12 Dec 1998) |
| elevator muscle of upper eyelid | <anatomy, muscle> Origin, orbital surface of the lesser wing of the sphenoid, above and anterior to the optic canal; insertion, skin of eyelid, tarsal plate, and orbital walls, by medial and lateral expansions of the aponeurosis of insertion; action, raises the upper eyelid; nerve supply, oculomotor. Synonym: musculus levator palpebrae superioris, elevator muscle of upper eyelid, musculus orbitopalpebralis, palpebralis. (05 Mar 2000) |
| eyelid | <anatomy> The cover of the eye; that portion of movable skin with which an animal covers or uncovers the eyeball at pleasure. Source: Websters Dictionary (01 Mar 1998) |
| upper eyelid | The superior, larger and more mobile of the two eyelids which covers most of the anterior surface of the eyeball, including the cornea, when closed; a portion of the lacrimal gland and the aponeurosis of the levator palpebrae superioris muscle extend into it, the muscle opening the closed eye and providing additional elevation when the gaze is directed upward. Synonym: palpebra superior, upper lid. (05 Mar 2000) |
| lower eyelid | The inferior, smaller and less mobile of the two eyelids; a check ligament from the inferior rectus muscle extends into it, pulling the lid inferiorly when the gaze is directed downward. Synonym: palpebra inferior, lower lid. (05 Mar 2000) |
| burns, third degree | In third degree burns the damage has progressed to the point of skin death. The skin is white and without sensation. (12 Dec 1998) |
| choroid plexus of third ventricle | The double row of vascular projections from the undersurface of the tela choroidea where it roofs over the third ventricle. Synonym: plexus choroideus ventriculi tertii. (05 Mar 2000) |
| choroid tela of third ventricle | A double fold of pia mater, enclosing subarachnoid trabeculae, between the fornix above and the epithelial roof of the third ventricle and the thalami below; at each lateral margin is a vascular fringe projecting into the choroidal fissure of the lateral ventricle; on its undersurface are several small vascular projections filling the folds of the ependymal roof of the third ventricle. Synonym: tela choroidea ventriculi tertii, tela choroidea superior, triangular lamella, velum interpositum, velum triangulare. (05 Mar 2000) |
| molar, third | The aftermost permanent tooth on each side in the maxilla and mandible. (12 Dec 1998) |
| pregnancy trimester, third | Period of pregnancy from the beginning of the 29th through the 42nd completed week (197 to 294 days) of gestation. (12 Dec 1998) |
| healing by third intention | The slow filling of a wound cavity or ulcer by granulations, with subsequent cicatrization. (05 Mar 2000) |