| midsigmoid sphincter | The physiological sphincter midway in the sigmoid colon. Synonym: iliopelvic sphincter. (05 Mar 2000) |
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| physiological 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) |
| colic sphincter | One of the physiological sphincter's of the colon. (05 Mar 2000) |
| musculus sphincter | <anatomy> A ringlike band of muscle fibres that constricts a passage or closes a natural orifice, also called musculus sphincter. Origin: L., Gr. Sphinkter = that which binds tight (18 Nov 1997) |
| musculus sphincter ampullae hepatopancreaticae | The smooth muscle sphincter of the hepatopancreatic ampulla within the duodenal papilla. Synonym: musculus sphincter ampullae hepatopancreaticae, Glisson's sphincter, hepatopancreatic sphincter, Oddi's sphincter. (05 Mar 2000) |
| musculus sphincter ani externus | A fusiform ring of striated muscular fibres surrounding the anus, attached posteriorly to the coccyx and anteriorly to the central tendon of the perineum; it is subdivided, often indistinctly, into a subcutaneous part, a superficial part and a deep part for descriptive purposes. Synonym: musculus sphincter ani externus, external sphincter muscle of anus. (05 Mar 2000) |
| musculus sphincter ani internus | <anatomy> A smooth muscle ring, formed by an increase of the circular fibres of the rectum, situated at the upper end of the anal canal, internal to the outer voluntary external anal sphincter. This sphincter is maximally-contracted when the rectal ampulla is at rest -empty or relaxed to accommodate a distending faecal mass. It is inhibited with filling of the ampulla, increased distension and peristalsis. Synonym: musculus sphincter ani internus, internal sphincter muscle of anus. (05 Mar 2000) |
| musculus sphincter ductus choledochi | 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) |
| musculus sphincter ductus pancreatici | 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) |
| musculus sphincter oris | <anatomy, muscle> Origin, by nasolabial band from septum of the nose, by superior incisive bundle from incisor fossa of maxilla, by inferior incisive bundle from lower jaw each side of symphysis; insertion, fibres surround mouth between skin and mucous membrane of lips and cheeks, and are blended with other muscles; action, closes lips; nerve supply, facial. Synonym: musculus orbicularis oris, musculus sphincter oris, orbicular muscle of mouth, sphincter oris. (05 Mar 2000) |
| musculus sphincter pupillae | A ring of smooth muscle fibres surrounding the pupillary border of the iris. Synonym: musculus sphincter pupillae, sphincter muscle of pupil. (05 Mar 2000) |
| musculus sphincter pylori | A thickening of the circular layer of the gastric musculature encircling the gastroduodenal junction. Synonym: musculus sphincter pylori, sphincter muscle of pylorus. (05 Mar 2000) |
| musculus sphincter urethrae | Origin, ramus of pubis; insertion, with fellow in median raphe behind and in front of urethra; action, constricts membranous urethra; nerve supply, pudendal. Synonym: musculus sphincter urethrae, external urethral sphincter, Guthrie's muscle, musculus compressor urethrae, musculus constrictor urethrae, musculus sphincter urethrae membranaceae, sphincter muscle of urethra, Wilson's muscle. (05 Mar 2000) |
| musculus sphincter urethrae membranaceae | Origin, ramus of pubis; insertion, with fellow in median raphe behind and in front of urethra; action, constricts membranous urethra; nerve supply, pudendal. Synonym: musculus sphincter urethrae, external urethral sphincter, Guthrie's muscle, musculus compressor urethrae, musculus constrictor urethrae, musculus sphincter urethrae membranaceae, sphincter muscle of urethra, Wilson's muscle. (05 Mar 2000) |
| musculus sphincter vaginae | <anatomy> In the male: origin, the perineal membrane fascia on the dorsum of the bulb of the penis; insertion, central tendon of the perineum and the median raphe on the free surface of the bulb; action, constricts bulbous urethra when attempting to expel last drops following urination, or spasmodically with ejaculation to expel semen. In the female: origin, the dorsum of the clitoris, the corpus cavernosum, and the perineal membrane; insertion, central tendon of the perineum; action, acts as a weak sphincter of the vagina; when developed, is a part of "cross-member musculature" of pelvic floor which resists prolapse of pelvic viscera. Nerve supply, pudendal (deep perineal branch). Synonym: musculus bulbospongiosus, musculus bulbocavernosus, musculus ejaculator seminis, musculus sphincter vaginae, sphincter vaginae. (05 Mar 2000) |