| sieve bone | A horizontal lamina from which are suspended the labyrinth, on either side, and the lamina perpendicularis in the centre; it fits into the ethmoidal notch of the frontal bone and supports the olfactory lobes of the cerebrum, being pierced with numerous openings for the passage of the olfactory nerves. Synonym: lamina cribrosa ossis ethmoidalis, cribrum, sieve bone, sieve plate. (05 Mar 2000) |
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| molecular sieve | A gel-like material with pore sizes of such ranges as to exclude molecules above certain sizes; used in fractionating or purifying macromolecules. (05 Mar 2000) |
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| sieve | 1. A utensil for separating the finer and coarser parts of a pulverized or granulated substance from each other. It consist of a vessel, usually shallow, with the bottom perforated, or made of hair, wire, or the like, woven in meshes. "In a sieve thrown and sifted." 2. A kind of coarse basket. <botany> Sieve cells, cribriform cells. See Cribriform. Origin: OE. Sive, AS. Sife; akin to D. Zeef, zift, OHG. Sib, G. Sieb. A. Cf. Sift. Source: Websters Dictionary (01 Mar 1998) |
| sieve graft | An obsolete term for a full-thickness skin graft taken after cutting multiple holes in it with a circular punch, thus leaving islands of skin in the donor area to heal it. (05 Mar 2000) |
| sieve plate | Perforated end walls separating the component cells (sieve elements) that make up the phloem sieve tubes in vascular plants. The perforations permit the flow of water and dissolved organic solutes along the tube and are lined with callose. The plates are readily blocked by further deposition of callose when the sieve tube is stressed or damaged. (18 Nov 1997) |
| sieve tube | The structure within the phloem of higher plants that is responsible for transporting organic material (sucrose, raffinose, amino acids, etc.) from the photosynthetic tissues (e.g. Leaves) to other parts of the plant. Made up of a column of cells (sieve elements) connected by sieve plates. (18 Nov 1997) |
| 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) |