| trapezoid bone | A bone in the distal row of the carpus; it articulates with the second metacarpal, trapezium, capitate, and scaphoid. Synonym: os trapezoideum, lesser multangular bone, os multangulum minus, trapezoid. (05 Mar 2000) |
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| ventral nucleus of trapezoid body | A cell group embedded among the fibres of the trapezoid body, the major decussation of the central auditory pathway, in the lower pons. The nucleus receives fibres from the contralateral cochlear nuclei and contributes fibres to the ascending auditory system or lateral lemniscus. Synonym: nucleus ventralis corporis trapezoidei. (05 Mar 2000) |
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| dorsal nucleus of trapezoid body | A circumscript, bipartite cell group located ventrolaterally in the lower pontine tegmentum, immediately dorsal to the trapezoid body; the nucleus receives fibres from both the ipsilateral and contralateral cochlear nuclei, and contributes fibres to the lateral (auditory) lemniscus of both sides. It is believed to be prominently involved in the function of spatial localization of sound. Synonym: nucleus dorsalis corporis trapezoidei, oliva superior, superior olivary nucleus, superior olive. (05 Mar 2000) |
| trapezoid | 1. <geometry> A plane four-sided figure, having two sides parallel to each other. 2. <anatomy> A bone of the carpus at the base of the second metacarpal, or index finger. Origin: Gr. Trapezoid-shaped; table + shape, likeness: cf. F. Trapezoide. See Trapezium. 1. Having the form of a trapezoid; trapezoidal; as, the trapezoid ligament which connects the coracoid process and the clavicle. 2. <anatomy> Of or pertaining to the trapezoid ligament; as, the trapezoid line. Source: Websters Dictionary (01 Mar 1998) |
| trapezoid body | A plate of transverse fibres running over the dorsal (deep) border of the pontine nuclei; it is formed by ascending auditory fibres that cross to the opposite side of the brainstem. Synonym: corpus trapezoideum, trapezoid. (05 Mar 2000) |
| trapezoid ligament | <anatomy> The lateral part of the coracoclavicular ligament that attaches to the trapezoid line of the clavicle. Synonym: ligamentum trapezoideum. (05 Mar 2000) |
| trapezoid line | The area on the inferior surface of the clavicle near its lateral extremity on which the trapezoid ligament attaches. Synonym: linea trapezoidea, trapezoid ridge. (05 Mar 2000) |
| trapezoid ridge | The area on the inferior surface of the clavicle near its lateral extremity on which the trapezoid ligament attaches. Synonym: linea trapezoidea, trapezoid ridge. (05 Mar 2000) |
| bone within a bone | <radiology> STOP heavy metal, S: sickle cell disease, T: Thorotrast, O: osteopetrosis, P: Paget's disease, heavy metals, hypervitaminosis D (12 Dec 1998) |
| acute reflex bone atrophy | Atrophy of bones, commonly of the carpal or tarsal bones, following a slight injury such as a sprain. See: causalgia, reflex sympathetic dystrophy. Synonym: acute reflex bone atrophy, posttraumatic osteoporosis, Sudeck's syndrome. Origin: L. English sweat (05 Mar 2000) |
| air-bone gap | The difference between the threshold for hearing acuity by bone conduction and by air conduction. (05 Mar 2000) |
| Albrecht's bone | A small bone between the basioccipital and basisphenoid. (05 Mar 2000) |
| allogeneic bone marrow transplant | <haematology, procedure> A bone marrow transplant using marrow collected from a matched healthy donor, usually a brother or sister. The risks associated with the transplant increase with age and 50 years of age is generally regarded as the upper limit. (13 Nov 1997) |
| alveolar bone | That portion of bone in either the maxilla or the mandible which surrounds and supports the teeth. (12 Dec 1998) |
| alveolar bone loss | The resorption of bone in the supporting structures of the maxilla or mandible as a result of periodontal disease. (12 Dec 1998) |
| alveolar supporting bone | alveolar process |