| vesicoureteral valve | <anatomy, urology> A lock mechanism in the wall of the intravesical portion of the ureter that normally prevents urinary reflux. (21 Jun 2000) |
|---|---|
| reducing valve | A valve designed to lower the pressure of a gas coming from a cylinder containing compressed gas under high pressure. (05 Mar 2000) |
| Vieussens' valve | The thin layer of white matter stretching between the two superior cerebellar peduncles, forming the roof of the superior recess of the fourth ventricle. Synonym: velum medullare superius, anterior medullary velum, Vieussens' valve. (05 Mar 2000) |
| caval valve | An endocardial fold extending from the anterior inferior margin of the inferior vena cava to the anterior part of the limbus fossa ovalis. Synonym: valvula venae cavae inferioris, caval valve, eustachian valve, sylvian valve. (05 Mar 2000) |
| Mercier's valve | An occasional fold of mucosa of the bladder partially occluding the ureteral orifice. (05 Mar 2000) |
| right atrioventricular valve | <anatomy> This heart valve, named for its three cusps (leaflets), divides the right atrium and the right ventricle. When the right atrium contracts blood flows through the tricuspid valve into the right ventricle. On closure, the tricuspid prohibits the backflow of blood into the right atrium. (19 Jan 1998) |
| Guerin's valve | A fold of mucous membrane sometimes found in the root of the navicular fossa of the urethra. Synonym: valvula fossae navicularis, Guerin's fold, Guerin's valve. (05 Mar 2000) |
| Rosenmuller's valve | A fold of mucous membrane guarding the lower opening of the nasolacrimal duct. Synonym: plica lacrimalis, Bianchi's valve, Hasner's fold, Hasner's valve, Huschke's valve, Rosenmuller's valve. (05 Mar 2000) |
| mitral valve | <anatomy, cardiology> The heart valve that divides the left atrium and left ventricle. During left atrial contraction, the mitral valve opens to allow blood to flow into the left ventricle. Upon closure, the mitral valve prohibits the regurgitation of blood back into the left atrium. The mitral valve is the only heart valve that has only 2 valve cusps (all others have 3). (13 Nov 1997) |
| mitral valve insufficiency | Backflow of blood from the left ventricle into the left atrium, owing to imperfect functioning of the mitral valve. (12 Dec 1998) |
| mitral valve prolapse | <cardiology> A systolic click-murmur syndrome, floppy-valve syndrome and billowing mitral leaflet syndrome. A common, but highly variable (most individuals are asymptomatic), clinical syndrome that has been described in up to 7% of all females in the 14 to 30 age group. There is also an increased familial incidence suggesting an autosomal dominant form of inheritance. Treatment often includes the avoidance of stimulants (caffeine, nicotine, decongestants) and the use of a beta-blocker medication in select cases. Inheritance: autosomal dominant. Synonym:: Barlow's syndrome. (13 Nov 1997) |
| mitral valve prolapse syndrome | <syndrome> The clinical constellation of findings with or without symptoms due to prolapse of the mitral valve: a nonejection systolic click accentuated in the standing posture, sometimes multiple, sometimes with mitral regurgitation occurring relatively late in systole, and accompanied by echocardiographic evidence of the mitral valve prolapse, usually with thickened leaflets of the valve. Symptoms are non-specific and may include vague chest pains and dyspnea on exertion. Synonym: billowing mitral valve syndrome. (05 Mar 2000) |
| mitral valve stenosis | A rheumatic disease causing diffuse thickening of the mitral valve leaflets by fibrous tissue or calcific deposits. (harrisons' principles of internal medicine, 13th ed, p1052) (12 Dec 1998) |
| congenital absence of pulmonary valve | <radiology> BIG central pulmonary arteries, big RV (12 Dec 1998) |
| congenital valve | An abnormal lining fold obstructing a passage; e.g., of a mucous membrane in the urethra. (05 Mar 2000) |