| first visceral cleft | <anatomy> The cleft between the hyoid and mandibular arches of the embryo; the external auditory meatus is developed from its dorsal portion. Synonym: first visceral cleft. (05 Mar 2000) |
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| 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 |
| amyloidosis: bone manifestations | <radiology> Joint pain without radiographic findings, osteoporosis, especially in axial skeleton, lytic lesions that destroy cortex and invade soft tissue, wrist, scaphoid and lunate lesions that may extend into the carpal tunnel, inducing the classic complaints of carpal tunnel syndrome amyloid arthropathy Differential diagnosis: pigmented villonodular synovitis, synovial chondromatosis, rheumatoid arthritis, TB (12 Dec 1998) |
| aneurysmal bone cyst | <radiology> ABC, 10 - 30 yrs, 75% before skeletal maturity, sites: long bones; also, flat bones Findings: metaphyseal if unfused, metaepiphyseal after fusion, lytic, expansile, thin, continuous rim, thin internal bony strands (12 Dec 1998) |
| ankle bone | 1. <anatomy> The astragalus. 2. <surgery> A variety of clubfoot (Talipes calcaneus). See the Note under Talipes. 1. A slope; the inclination of the face of a work. 2. <geology> A sloping heap of fragments of rock lying at the foot of a precipice. Origin: L, the ankle, the ankle bone. (26 Nov 1998) |
| anterior condyloid canal of occipital bone | The canal through which the hypoglossal nerve emerges from the skull. Synonym: canalis hypoglossalis, anterior condyloid canal of occipital bone, anterior condyloid foramen. (05 Mar 2000) |
| anterior surface of petrous part of temporal bone | The surface of the petrous part of the temporal bone contributing to the floor of the middle cranial fossa. Synonym: facies anterior partis petrosae ossis temporalis. (05 Mar 2000) |
| apex of petrous part of temporal bone | The irregular antero-medial extremity of the petrous part on which the anterior end of the carotid canal opens. Synonym: apex partis petrosae ossis temporalis. (05 Mar 2000) |