| ostial sphincter | A thickening of circular muscular fibres at the level of an orifice. (05 Mar 2000) |
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| external anal sphincter | 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) |
| external sphincter muscle of anus | 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) |
| extrinsic sphincter | A sphincter provided by circular muscular fibres extraneous to the organ. (05 Mar 2000) |
| unicanalicular sphincter | A sphincter limited to one visceral canal or tube. (05 Mar 2000) |
| urinary sphincter, artificial | An artifical implanted device, usually in the form of an inflatable silicone cuff, inserted in or around the bladder neck in the surgical treatment of urinary incontinence caused by sphincter weakness. Often it is placed around the bulbous urethra in adult males. The artificial urinary sphincter is considered an alternative to urinary diversion. (12 Dec 1998) |
| first duodenal sphincter | The sphincter supposedly located at the level of the aboral extremity of the duodenal bulb. (05 Mar 2000) |
| functional 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) |
| lower oesophageal sphincter | <anatomy> A muscular sphincter located at the junction of the oesophagus and the stomach. On closure the lower oesophageal sphincter prevents the back wash (reflux) of stomach acid into the oesophagus where it may damage the mucosa. See: gastrooesophageal reflux disease. (16 Mar 1998) |
| abdominal internal oblique muscle | <anatomy, muscle> Origin, iliac fascia deep to lateral part of inguinal ligament, anterior half of crest of ilium, and lumbar fascia; insertion, tenth to twelfth ribs and sheath of rectus; some of the fibres from inguinal ligament terminate in the conjoint tendon; action, diminishes capacity of abdomen, flexes lumbar vertebral column (bends thorax forward); nerve supply, lower thoracic. Synonym: musculus obliquus internus abdominis, abdominal internal oblique muscle. (05 Mar 2000) |
| anterior intercostal branches of internal thoracic artery | One of the arteries supplying the anterior portions of the intercostal spaces of the thoracic wall. Anterior intercostal arteries 1-6 arise as branches of the internal thoracic artery; 7-11 arise as branches of the musculophrenic artery. Synonym: rami intercostales anteriores, rami intercostalis anteriores arteria thoracica interna. (05 Mar 2000) |
| anterior limb of internal capsule | The portion of the internal capsule between the head of the caudate nucleus and the putamen; it lies anterior to the genu of the internal capsule. Synonym: crus anterius capsulae internae. (05 Mar 2000) |
| aponeurosis of internal abdominal oblique muscle | <anatomy> Broad, flat tendinous portion of the internal abdominal oblique muscle. The fleshy fibres of the muscle end in the aponeurosis lateral to the semilunar line. The uppermost portion of the aponeurosis is attached to the outer surfaces and lower borders of the seventh to ninth costal cartilages. Of the portion extending between the costoxiphoid margin and the pubis, the upper two-thirds splits into anterior and posterior laminae at the lateral border of the rectus abdominis muscle to contribute to the anterior and posterior walls of the sheath of the rectus abdominis muscle as they extend to the midline linea alba. The lower third of the aponeurosis does not split but joins the aponeuroses of the external abdominal oblique and transversus abdominis muscles to form the anterior wall of the sheath of the rectus abdominis muscle. The fibres of the portion of the aponeurosis contributing to the rectus sheath decussate with those of the contralateral aponeurosis in the linea alba. The lowermost portion of the aponeurosis blends with the aponeurosis of the transversus abdominis muscle to form the conjoint tendon, attaching to the pubic crest and often the pecten pubis, thus forming the posterior wall of the inguinal canal at the superficial inguinal ring. See: cremasteric fascia, conjoint tendon, rectus sheath. (05 Mar 2000) |
| basal tentorial branch of internal carotid artery | <anatomy, artery> A small branch from the cavernous part of the internal carotid artery to the base of the tentorium. Synonym: ramus basalis tentorii arteriae carotidis internae. (05 Mar 2000) |
| ganglionic branch of internal carotid artery | <anatomy, artery> Branch to trigeminal ganglion; a small branch of the cavernous part of the internal carotid artery to the trigeminal ganglion. Synonym: ramus ganglii trigeminalis. (05 Mar 2000) |