- 1. A small circumscribed area differing in color or structure from the surrounding surface. 2. In dermatology, a flat area greater than 1.0 cm in diameter. 3. An intermediate stage in the formation of a cap on the surface of a cell.- p. clamping a technique used in the study of ion channels in which the movement of ions across a small p. of isolated membrane is measured when the membrane is electrically polarized or hyperpolarized and maintained at that potential. SYN: p. clamp.- cotton-wool patches white, fuzzy areas on the surface of the retina (accumulations of cellular organelles) caused by damage (usually infarction) of the retinal fiber layer. SYN: cotton-wool spots.- herald p. the initial rapidly enlarging oval-shaped red papulosquamous lesion, usually on the trunk, heralding the widespread eruption of pityriasis rosea, and preceding the latter by 7–14 days.- Hutchinson p. SYN: salmon p..- mucous p. an oval to round, yellow-gray to white, membrane-covered lesion or lesions occurring on the mucous membranes; usually seen in secondary syphilis.- salmon p. 1. an intraretinal hemorrhage seen in sickle cell retinopathy; 2. the appearance of an orbital lymphoid tumor as seen in the subconjunctival space; 3. a common macular orange-pink to red vascular malformation present at or near birth on the head and neck that involutes during childhood. SYN: Hutchinson p..- shagreen p. SYN: shagreen skin.- smoker's patches SYN: leukoplakia.- soldier's patches SYN: milk spots (1), under spot.* * *planned approach to community health
* * *patch 'pach nb) a usu. disk-shaped piece of material that is worn on the skin and contains a substance (as a drug) that is absorbed at a constant rate through the skin and into the bloodstream <a nicotine \patch> called also skin patchc) a shield worn over the socket of an injured or missing eye2) a circumscribed region of tissue (as on the skin or in a section from an organ) that differs from the normal color or composition <sometimes great white \patches develop on the tongue, the cheeks, and the gums (Morris Fishbein)>patch vt
* * *(pach) [L. pittacium; Gr. pittakion] 1. any area that differs in color or texture from the surrounding surface and is not elevated above it; see also macule and spot. 2. a small piece of cloth or other material that covers part of another surface. a 3. macule more than 1 cm in diameter.
Medical dictionary. 2011.