| ureteric bud | The primordial cellular outgrowth from the mesonephric duct that gives rise to the epithelial lining of the ureter, of the pelvis, and calyces of the kidney, and of the straight collecting tubules. Synonym: ureteric bud. (05 Mar 2000) |
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| limb bud | The limbs of vertebrates start as outpushings of mesenchyme surrounded by a simple epithelium. The distal region is referred to as the progress zone. There has been extensive study of positional information within the limb bud that determines, for example: the proximal distal pattern of bone development and the anterior posterior specification of digits. (18 Nov 1997) |
| liver bud | The primordial cellular diverticulum of the embryonic foregut endoderm that gives rise to the parenchyma of the liver. (05 Mar 2000) |
| lung bud | The endodermal lung primordium which will give rise to the epithelial lining of the respiratory tract. Synonym: lung bud. (05 Mar 2000) |
| angel's wing | A deformity in which both scapulae project conspicuously. See: winged scapula. (05 Mar 2000) |
| ashen wing | A prominence in the floor of the inferior fovea of the fourth ventricle that overlies the dorsal motor nucleus of the vagus. Synonym: trigonum nervi vagi, ala cinerea, ashen wing, gray wing, trigone of vagus nerve, va'gi eminentia. (05 Mar 2000) |
| gray wing | A prominence in the floor of the inferior fovea of the fourth ventricle that overlies the dorsal motor nucleus of the vagus. Synonym: trigonum nervi vagi, ala cinerea, ashen wing, gray wing, trigone of vagus nerve, va'gi eminentia. (05 Mar 2000) |
| greater wing of sphenoid bone | Strong squamous processes extending in a broad superolateral curve from the body of the sphenoid bone. The greater wing presents these suraces (facies): 1) cerebral surface: forms anterior third of the floor of the lateral portions of the middle cranial fossa; 2) temporal surface: forms the deepest portion of the temporal fossa; 3) infratemporal surface, forms the "roof" of the infratemporal fossa; 4) orbital surface: forms posterolateral wall of orbit. The greater wing forms the inferior border of the supraorbital fissure, and is perforated at its root by foramina rotundum ovale, and spinosum and the pterygoid canal. Synonym: ala major ossis sphenoidalis, ala temporalis. (05 Mar 2000) |
| wing | <plant biology> A membranous expansion of a fruit or seed, which aids dispersal, a thin flange of tissue extended beyond the normal outline of a stem or petiole, a lateral petal of a flower in the family Fabaceae. (09 Oct 1997) |
| wing-beating tumour | A coarse, irregular tumour that is most prominent when the limbs are held outstretched, reminiscent of a bird flapping its wings; due to up and down excursion of arm at abducted shoulder. Seen mainly with Wilson's disease. (05 Mar 2000) |
| wing cell | One of the polyhedral cell's in the corneal epithelium beneath the surface layer. (05 Mar 2000) |
| wing-footed | 1. Having wings attached to the feet; as, wing-footed Mercury; hence, swift; moving with rapidity; fleet. 2. <zoology> Having part or all of the feet adapted for flying. Having the anterior lobes of the foot so modified as to form a pair of winglike swimming organs; said of the pteropod mollusks. Source: Websters Dictionary (01 Mar 1998) |
| wing-handed | <zoology> Having the anterior limbs or hands adapted for flight, as the bats and pterodactyls. Source: Websters Dictionary (01 Mar 1998) |
| wing-leaved | <botany> Having pinnate or pinnately divided leaves. Source: Websters Dictionary (01 Mar 1998) |
| wing of crista galli | A small lateral expansion of the ethmoid bone from the front of the crista galli on each side that articulates with the frontal bone and forms the foramen caecum. Synonym: ala cristae galli, alar process. (05 Mar 2000) |