| urethral valves | Folds in the urethral mucous membrane. See: anterior urethral valve, posterior urethral valves. (05 Mar 2000) |
|---|---|
| anal sphincter | See: external anal sphincter, internal anal sphincter. (05 Mar 2000) |
| anatomical sphincter | An accumulation of muscular circular fibres or specially arranged oblique fibres the function of which is to reduce partially or totally the lumen of a tube, the orifice of an organ, or the cavity of a viscus; the closing component of a pylorus. (05 Mar 2000) |
| annular sphincter | A short thickening of circular muscular fibres, similar to a ring; a ring-shaped sphincter as opposed to a segmental sphincter. (05 Mar 2000) |
| antral sphincter | Angular sphincter, thickening of the circular muscular layer forming a proposed intermediate sphincter at the level of the angular notch of the stomach. While the thickening of the circular muscle may indicate the commencement of the pyloric antrum, true functional sphincteric activity distinct from the other peristaltic contractions of the stomach is not observed although some of these may in fact temporarily close off the antrum from the remainder of the stomach lumen. Synonym: antral sphincter, midgastric transverse sphincter, sphincter antri, sphincter intermedius, sphincter of antrum, sphincter of gastric antrum. (05 Mar 2000) |
| artificial sphincter | A sphincter produced by surgical procedures to reduce speed of flow in the digestive system or to maintain continence of the intestine. (05 Mar 2000) |
| basal sphincter | The thickening of the circular muscular coat at the base of the ileal papilla at the terminal ileum. Synonym: sphincteroid tract of ileum. (05 Mar 2000) |
| bicanalicular sphincter | A sphincter encircling two canals, such as the terminal portions of the common bile duct and the main pancreatic duct. (05 Mar 2000) |
| Boyden's sphincter | Smooth muscle sphincter of the common bile duct immediately proximal to the hepatopancreatic ampulla; it is this sphincter that controls the flow of bile in the duodenum. Synonym: musculus sphincter ductus choledochi, Boyden's sphincter, choledochal sphincter, sphincter muscle of common bile duct. (05 Mar 2000) |
| canalicular sphincter | A sphincter located somewhere along the course of an organ, a tube, or a duct, as opposed to ostial sphincter. (05 Mar 2000) |
| macroscopic sphincter | A sphincter visible to the naked eye. (05 Mar 2000) |
| palatopharyngeal sphincter | A constant band of the superior pharyngeal constrictor muscle which sweeps posteriorly from the anterolateral part of the superior surface of the palatine aponeurosis. It creates a visible ridge when the superior constrictor is contracted, meeting the elevated soft palate to seal off the pharyngeal isthmus during swallowing. Synonym: pharyngeal ridge, sphincter of the pharyngeal isthmus, velopharyngeal sphincter. (05 Mar 2000) |
| radiological sphincter | A section of a tubular structure that acts as if it has a band of circular muscle to constrict it, although no such specialised structure can be found on morphological examination. Synonym: functional sphincter, radiological sphincter. (05 Mar 2000) |
| Varolius' sphincter | A thickening of circular musculature at the free margin of the ileal papilla. Synonym: ileocaecocolic sphincter, marginal sphincter, operculum ilei, Varolius' sphincter. (05 Mar 2000) |
| pancreatic sphincter | Smooth muscle sphincter of the main pancreatic duct immediately proximal to the hepatoduodenal, ampulla. Synonym: musculus sphincter ductus pancreatici, pancreatic sphincter, sphincter muscle of pancreatic duct. (05 Mar 2000) |