| Duret's lesion | Small haemorrhage(s) in the floor of the fourth ventricle or beneath the aqueduct of Sylvius. (05 Mar 2000) |
|---|---|
| Janeway lesion | One of the stigmata of infectious endocarditis: irregular, erythematous, flat, painless macules on the palms, soles, thenar and hypothenar eminences of the hands, tips of the fingers, and plantar surfaces of the toes; rarely a diffuse rash. In acute endocarditis the lesions may be haemorrhagic or purple. (05 Mar 2000) |
| upper motor neuron lesion | Injury to cerebral descending (corticonuclear) fibres above the brainstem or spinal motor nerve nucleus. Synonym: upper motor neuron lesion. (05 Mar 2000) |
| Lennert's lesion | <tumour> Malignant lymphoma with a high proportion of diffusely scattered epithelioid cells, tonsillar involvement, and an unpredictable course. Synonym: Lennert's lesion. (05 Mar 2000) |
| lesion | <pathology> Any pathological or traumatic discontinuity of tissue or loss of function of a part. Origin: L. Laesio, laedere = to hurt (18 Nov 1997) |
| Lohlein-Baehr lesion | Focal embolic glomerulonephritis occurring in bacterial endocarditis. Synonym: Baehr-Lohlein lesion. (05 Mar 2000) |
| lower motor neuron lesion | Injury to motor cells in the brainstem or spinal cord, or of the axons derived from them. (05 Mar 2000) |
| anterior focal point | The point where parallel rays from the retina are focused. (05 Mar 2000) |
| back focal length | <microscopy> As measured on the principal axis, from the second lens vertex to the back focal point of the lens. It is not the equivalent of the focal length. (05 Aug 1998) |
| back focal plane | <microscopy> The plane, normal to the lens axis, situated at the back focus of a lens. (05 Aug 1998) |
| Berger's focal glomerulonephritis | Glomerulonephritis affecting a small proportion of renal glomeruli which commonly presents with haematuria and may be associated with acute upper respiratory infection in young males, not usually due to streptococci; associated with IgA deposits in the glomerular mesangium and may also be associated with systemic disease, as in Henoch-Schonlein purpura. Synonym: Berger's disease, Berger's focal glomerulonephritis, focal nephritis, IgA nephropathy. (05 Mar 2000) |
| glomerulosclerosis, focal | Glomerular disease characterised by focal and segmental areas of glomerular sclerosis, usually commencing in the juxtamedullary glomeruli and gradually spreading to involve other parts of the kidney, with eventual kidney failure. (12 Dec 1998) |
| chronic focal sclerosing osteomyelitis | A reaction of bone to a mild bacterial infection, often the result of a carious tooth, in persons with a high degree of tissue resistance; results in a localised radio-opacity. Synonym: focal condensing osteitis. (05 Mar 2000) |
| plane, focal | <microscopy> A plane through the focal point perpendicular to the principle axis of a lens or mirror. (05 Aug 1998) |
| positive focal length | <microscopy> Any lens which converges parallel rays to a focus at the back of the lens is a positive lens and has a positive focal length. The focal length is measured from the second principal point of the lens to the point on the lens axis where the rays from an infinitely distant point are brought to focus. See: negative focal length. (05 Aug 1998) |