| aortic valve insufficiency | Backflow of blood from the aorta into the left ventricle, owing to imperfect functioning of the aortic semilunar valve. (12 Dec 1998) |
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| aortic valve prolapse | The downward displacement of the cuspal material (misalignment of the cusps) below a line joining points of attachment of the aortic valve leaflets. The prolapsed cusp may occlude the ventricular septal defect during ventricular diastole. (12 Dec 1998) |
| aortic valve stenosis | Narrowing of the orifice of the aortic valve or of the supravalular or subvalvular regions. (12 Dec 1998) |
| artificial heart valve | <cardiology> A synthetic or porcine (pigskin) valve surgically placed into the heart to replace a defective or malfunctioning valve. The aortic and mitral valves are the most frequently replaced with artificial valves. (27 Sep 1997) |
| ball valve | Any of a variety of prosthetic cardiac valve's comprised of a ball within a retaining cage affixed to the orifice; when appropriately sized, used in aortic, mitral, or tricuspid position. (05 Mar 2000) |
| ball valve action | The intermittent blockage of a tube or outlet of a cavity by some object or material that permits passage in one direction but not in the other. (05 Mar 2000) |
| ball-valve thrombus | Ball thrombus intermittently occluding the mitral or tricuspid orifice. (05 Mar 2000) |
| Bauhin's valve | The bilabial prominence of the terminal ileum into the large intestine at the caecocolic junction as seen in cadavers; in the living individual it appears as a truncated cone with a star-shaped orifice. Synonym: valva ileocaecalis, Bauhin's valve, ileocaecal eminence, ileocolic valve, Tulp's valve, Tulpius' valve, valve of Varolius. (05 Mar 2000) |
| Beraud's valve | A small fold in the interior of the lacrimal sac at its junction with the lacrimal duct. Synonym: Krause's valve. (05 Mar 2000) |
| Bianchi'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) |
| bicuspid aortic valve | See: familial aortic ectasia syndrome. (05 Mar 2000) |
| bicuspid 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) |
| bi-leaflet valve | A low profile mechanical heart valve that is less obstructive to outflow, especially in small size. (05 Mar 2000) |
| Bjork-Shiley valve | A low profile tilting disc mechanical heart valve. (05 Mar 2000) |
| Bochdalek's valve | A fold of mucous membrane in the lacrimal canaliculus at the lacrimal punctum. Synonym: Foltz' valvule. (05 Mar 2000) |