| lamellar bone | The normal type of adult mammalian bone, whether cancellous or compact, composed of parallel lamellae in the former and concentric lamellae in the latter; lamellar organization reflects a repeating pattern of collagen fibroarchitecture. (05 Mar 2000) |
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| ichthyosis, lamellar | A chronic, congenital ichthyosis inherited as an autosomal recessive trait. Infants are usually born encased in a collodion membrane which sheds within a few weeks. Scaling is generalised and marked with grayish-brown quadrilateral scales, adherent at their centres and free at the edges. In some cases, scales are so thick that they resemble armored plate. (12 Dec 1998) |
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| lamellar | 1. Arranged in thin plates or scales. Synonym: lamellate, lamellated. 2. Relating to lamellae. (05 Mar 2000) |
| lamellar cataract | A cataract in which the opacity is limited to the cortex. Synonym: zonular cataract. (05 Mar 2000) |
| lamellar granule | A membrane-bound granule, 100 to 500 nm in diameter, located in the upper layers of the stratum spinosum of certain stratified squamous epithelia. Synonym: lamellar granule, membrane-coating granule, Odland body. (05 Mar 2000) |
| lamellar ichthyosis | A dry form of congenital ichthyosiform erythroderma, an autosomal recessive trait present at birth; characterised by large, coarse scales over most of the body with thickened palms and soles, and associated with ectropion; histologically, there is hyperkeratosis, a prominent granular layer in the epidermis, slight acanthosis, many mitotic figures, and normal or reduced epidermal cell turnover. See: collodion baby, harlequin foetus. (05 Mar 2000) |
| lamellar keratoplasty | Keratoplasty in which only the anterior layer of the cornea is used (not a tectonic keratoplasty). Synonym: lamellar keratoplasty, layered keratoplasty. (05 Mar 2000) |
| lamellar phase | <biochemistry> A lamellar organisation of phospholipids that are packed as a bilayer with hydrophobic acyl tails inwardly directed and polar head groups on the outside surfaces. It is this bilayer that forms the basis of membranes in cells, though in most cellular membranes a very substantial proportion of the area may be occupied by integral proteins. The triple layered appearance of membranes seen in electron microscopy is thought to arise because the osmium tetroxide binds to the polar regions leaving a central, unstained, hydrophobic region. (31 Dec 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 |