- 1. A fold of the lining membrane of a canal or other hollow organ serving to retard or prevent a reflux of fluid. 2. Any formation or reduplication of tissue, or flaplike structure, resembling or functioning as a v.. SEE ALSO: valvule, plica. SYN: valva [TA]. [L. valva]- anal valves [TA] delicate crescent-shaped mucosal folds that pass between the lower ends of neighboring anal columns; the small pocket thus formed is an anal sinus. SYN: valvulae anales [TA], Morgagni valves.- aortic v. [TA] the v. between the left ventricle and the ascending aorta, consisting of three fibrous semilunar cusps (valvules), located in the adult in anterior, right posterior, and left posterior positions; they are named, however, in accordance with their embryonic derivation in which the anteriorly located cusp is the right cusp (above which the right coronary artery arises), the left posteriorly positioned cusp is designated as the left cusp (above which the left coronary artery arises), and the right posteriorly positioned cusp is designated as the posterior or noncoronary cusp. SYN: valva aortae [TA].- ball v. any of a variety of prosthetic cardiac valves comprising a ball within a retaining cage affixed to the orifice; when appropriately sized, used in aortic, mitral, or tricuspid position.- Béraud v. a small fold in the interior of the lacrimal sac at its junction with the lacrimal duct. SYN: Krause v..- bi-leaflet v. a low profile mechanical heart v. that is less obstructive to outflow, especially in small size.- biologic v. SYN: tissue v..- Blom-Singer v. a prosthesis for maintaining the patency of a tracheoesophageal puncture for vocal rehabilitation after laryngectomy.- Bochdalek v. a fold of mucous membrane in the lacrimal canaliculus at the lacrimal punctum. SYN: Foltz valvule.- congenital v. an abnormal lining fold obstructing a passage; e.g., of a mucous membrane in the urethra.- v. of coronary sinus [TA] a delicate fold of endocardium at the opening of the coronary sinus into the right atrium. SYN: valvula sinus coronarii [TA], coronary v., thebesian v..- v. of foramen ovale [TA] a fold projecting into the left atrium from the margin of the foramen ovale in the fetus; when, with beginning inspiration, the blood pressure within the left atrium increases, the v. closes and its edges become adherent to the margin of the foramen ovale, occluding it. SYN: valvula foraminis ovalis [TA], falx septi, v. of oval foramen.- Heyer-Pudenz v. a v. used in the shunting procedure for hydrocephaly; consisting of a catheter-v. system in which the ventricular catheter leads the cerebrospinal fluid into a one-way pump through which the cerebrospinal fluid passes down the distal catheter into the right atrium of the heart.- Hoboken valves the flangelike protrusions into the lumen of the umbilical arteries where they are twisted or kinked in their course through the umbilical cord.- v. of inferior vena cava [TA] an endocardial fold extending from the anterior inferior margin of the inferior vena cava to the anterior part of the limbus fossa ovalis. SYN: valvula venae cavae inferioris [TA], caval v., eustachian v., sylvian v..- Krause v. SYN: Béraud v..- mitral v. [TA] the v. closing the orifice between the left atrium and left ventricle of the heart; its two cusps are called anterior and posterior. SYN: valva atrioventricularis sinistra [TA], left atrioventricular v., valva mitralis, bicuspid v., valvula bicuspidalis.- nasal v. the variable aperture between the nasal septum and the caudal margin of the upper lateral nasal cartilage.- v. of navicular fossa [TA] an inconstant fold of mucous membrane sometimes found in the root of the navicular fossa of the urethra. SYN: valvula fossae navicularis [TA], Guérin fold, Guérin v..- parachute mitral v. congenital abnormality of the mitral v. characterized by the presence of a single papillary muscle from which the chordae of both v. leaflets divide; thus the resemblance to a parachute; the condition often produces a stenosis as the combined result of the tugging action of the chordae on, and the subsequent narrowing between, the leaflets. SYN: parachute deformity.- posterior urethral valves anomalous folds occurring at the level of the seminal colliculus. SYN: Amussat valvula.- prosthetic valves valves used to replace human valves. They are divided into mechanical and tissue valves. The tissue is divided into homografts and heterografts.- pulmonary v. [TA] the v. at the entrance to the pulmonary trunk from the right ventricle; it consists of semilunar cusps (valvules), which are usually arranged in the adult in right anterior, left anterior, and posterior positions; however, they are named in accordance with their embryonic derivation; thus the posteriorly located cusp is designated as the left cusp, the right anteriorly located cusp is designated the right cusp, and the left anteriorly positioned cusp is called the anterior cusp. SYN: valva trunci pulmonalis [TA], pulmonic v., v. of pulmonary trunk.- reducing v. a v. designed to lower the pressure of a gas coming from a cylinder containing compressed gas under high pressure.- Rosenmüller v. SYN: lacrimal fold.- semilunar v. [TA] a heart v. comprised of a set of three semilunar cusps (valvules); hence both the aortic and pulmonary valves are semilunar valves. SYN: valvula semilunaris [TA].- Terrien v. a valvelike fold between the gallbladder and the cystic duct; the first ridge of the spiral fold of the cystic duct.- tissue v. a prosthetic cardiac v. derived from the pig heart, bovine pericardium, or other biologic source. SEE ALSO: prosthesis. SYN: biologic v..- tricuspid v. [TA] the v. closing the orifice between the right atrium and right ventricle of the heart; its three cusps are called anterior, posterior, and septal. SYN: valva atrioventricularis dextra [TA], right atrioventricular v., valva tricuspidalis, valvula tricuspidalis.- Tulp v., Tulpius v. SYN: ileal papilla.- urethral valves folds in the urethral mucous membrane. SEE ALSO: anterior urethral v., posterior urethral valves.- v. of Varolius SYN: ileal papilla.- venous v. [TA] a fold of the lining layer of a vein to prevent a reflux of blood. SYN: valvula venosa (2) [TA].- v. of vermiform appendix a fold of mucous membrane, simulating a v., sometimes found at the origin of the vermiform appendix. SYN: Gerlach v., valvula processus vermiformis.- vesicoureteral v. a lock mechanism in the wall of the intravesical portion of the ureter that normally prevents urinary reflux.- v. of Vieussens a prominent v. in the great cardiac vein where it turns around the obtuse margin to become the coronary sinus.
* * *valve 'valv n1) a bodily structure (as the mitral valve) that closes temporarily a passage or orifice or permits movement of fluid in one direction only2) any of various mechanical devices by which the flow of liquid (as blood) may be started, stopped, or regulated by a movable part that opens, shuts, or partially obstructs one or more ports or passageways also the movable part of such a device
* * *n.a structure found in some tubular organs or parts that restricts the flow of fluid within them to one direction only. Valves are important structures in the heart, veins, and lymphatic vessels. Such a valve consists of two or three cusp fastened like pockets to the walls of the vessel. Blood flowing in the right direction flattens the cusps to the walls, but when flow is reversed the cusps become filled with blood or lymph and dilate to block the opening. See also mitral valve, tricuspid valve, semilunar valve.
* * *(valv) a membranous fold in a canal or passage that prevents reflux of the contents passing through it; see also valva and valvula. valval, valvar, valvular adj
Medical dictionary. 2011.