| hypophyseal pouch | A tubular outgrowth of ectoderm from the stomodeum of the embryo; it grows dorsad toward the infundibular process of the diencephalon, around which it forms a cup-like mass, giving rise to the pars distalis and pars juxtaneuralis of the hypophysis. Synonym: craniopharyngeal canal, hypophyseal pouch, Rathke's diverticulum, Rathke's pocket, Rathke's pouch. (05 Mar 2000) |
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| sphincter of third portion of duodenum | A physiological sphincter supposedly located at the horizontal (inferior) portion of the duodenum. (05 Mar 2000) |
| styloid process of third metacarpal bone | A pointed projection from the dorsolateral angle of the base of the third metacarpal bone; it sometimes exists as a separate ossicle. Synonym: processus styloideus ossis metacarpalis III. (05 Mar 2000) |
| superficial inguinal pouch | A pocket formed between Scarpa's and external oblique fascia adjacent to external inguinal ring; a common lodging site for undescended testes (as in cryptorchism). Synonym: superficial inguinal pouch. (05 Mar 2000) |
| superficial perineal pouch | The superficial compartment of the perineum; the space bounded above by the perineal membrane (inferior fascia of the urogenital diaphragm) and below by the superficial perineal (Colles') fascia; it contains the root structure of the penis or clitoris and associated musculature, plus the superficial transverse perineal muscle and, in the female only, the greater vestibular glands. Synonym: spatium perinei superficiale, Colles' space, superficial perineal pouch. (05 Mar 2000) |
| deep perineal pouch | The region between the perineal membrane and the endopelvic fascia of the floor of the pelvis occupied by the membranous part of the urethra, the bulbourethral gland (in the male), the deep transverse perineal and sphincter urethrae muscles, and the dorsal nerve and artery of the penis or clitoris. Synonym: spatium perinei profundum, deep perineal pouch. (05 Mar 2000) |
| Denis Browne's pouch | A pocket formed between Scarpa's and external oblique fascia adjacent to external inguinal ring; a common lodging site for undescended testes (as in cryptorchism). Synonym: superficial inguinal pouch. (05 Mar 2000) |
| douglas' pouch | A sac or recess formed by a fold of the peritoneum. (12 Dec 1998) |
| ileoanal pouch | A pouch constructed from the ileum and anastomosed to the proximal anus for restoration of normal continence after proctocolectomy. Kock pouch, a continent ileostomy with a reservoir and valved opening fashioned from doubled loops of ileum. Synonym: Kock ileostomy. (05 Mar 2000) |
| third | 1. Next after the second; coming after two others; the ordinal of three; as, the thirdhour in the day. "The third night." 2. Constituting or being one of three equal parts into which anything is divided; as, the third part of a day. Third estate. In England, the commons, or the commonalty, who are represented in Parliament by the House of Commons. In France, the tiers etat. See Tiers etat. Third order See Third. Origin: OE. Thirde, AS. Ridda, fr. Ri, reo, three; akin to D. Derde third, G. Dritte, Icel. Rii, Goth. Ridja, L. Tertius, Gr, Skr. Ttiya. See Three, and cf. Riding a jurisdiction, Tierce. Source: Websters Dictionary (01 Mar 1998) |
| third corpuscle | <haematology> A discoid cell (3m diameter) found in large numbers in blood, important for blood coagulation and for haemostasis by repairing breaches (small breaks) in the walls of blood vessels. Platelet _ granules contain lysosomal enzymes, dense granules contain ADP (a potent platelet aggregating factor) and serotonin (a vasoactive amine). They also release platelet-derived growth factor which presumably contributes to later repair processes by stimulating fibroblast proliferation. Synonym: thrombocytes. (09 Oct 1997) |
| third cranial nerve | <anatomy, nerve> Responsible for motor enervation of upper eyelid muscle, extraocular muscle and pupillary muscle. Lesions of the oculomotor nerve results in ptosis (dropping eyelid), deviation of the eyeball outward, double vision and a dilated pupil. (27 Sep 1997) |
| third cuneiform bone | A bone of the distal row of the tarsus; it articulates with the intermediate cuneiform, cuboid, navicular, and second, third, and fourth metatarsal bones. Synonym: os cuneiforme laterale, third cuneiform bone, wedge bone. (05 Mar 2000) |
| third degree burn | A burn involving destruction of the entire skin; deep third-degree burns extend into subcutaneous fat, muscle, or bone and often cause much scarring. Synonym: full-thickness burn. (05 Mar 2000) |
| third disease | <disease, virology> An acute, usually benign, infectious disease caused by a togavirus and most often affecting children and nonimmune young adults, in which the virus enters the respiratory tract via droplet nuclei and spreads to the lymphatic system. It is characterised by a slight cold, sore throat and fever, followed by enlargement of the postauricular, suboccipital and cervical lymph nodes and the appearances of a fine pink rash that begins on the head and spreads to become generalised. Synonym: German measles, rubeola. Origin: L. Rubellus = reddish, ruber = red (17 Dec 1997) |