| EFL | effective focal length |
|---|---|
| FCD | feces collection device; fibrocystic disease; fibrocystic dysplasia; focal cytoplasmic degradation |
| FD | familial dysautonomia; family doctor; fan douche; fatal dose; fetal danger; fibrin derivative; fibro... |
| FDH | familial dysalbuminemic hyperthyroxinemia; focal dermal hypoplasia; formaldehyde dehydrogenase |
| FEH | focal epithelial hyperplasia |
| 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) |
| posterior focal point | The point of a compound optical system where parallel rays entering the system are focused. (05 Mar 2000) |
| cutaneous focal mucinosis | Flesh-coloured papules of the skin, composed of homogenous mucinous material with scattered fibroblasts. (05 Mar 2000) |
| proximal femoral focal deficiency | A congenital defect in which variable portions of the upper end of the femur are reduced or absent. (05 Mar 2000) |
| negative focal length | <physics> The focal length of a negative lens. Parallel rays impinging on a negative lens can be traced to a virtual focus which exists on the same side of the lens as the impinging rays. The distance from the second principal point of the lens to this second focal point is measured on the same side of the lens as is the object. See: negative lens, focal length. (05 Aug 1998) |
| dystonia, focal, due to blepharospasm | The second most common focal dystonia, the involuntary, forcible closure of the eyelids. The first symptoms may be uncontrollable blinking. Only one eye may be affected initially, but eventually both eyes are usually involved. The spasms may leave the eyelids completely closed causing functional blindness even though the eyes and vision are normal. (12 Dec 1998) |
| dystonia, focal, due to torticollis | Spasmodic torticollis, or torticollis, is the most common of the focal dystonias. In torticollis, the muscles in the neck that control the position of the head are affected, causing the head to twist and turn to one side. In addition, the head may be pulled forward or backward. (12 Dec 1998) |
| oral focal mucinosis | An area of myxomatous connective tissue; the mucosal counterpart of cutaneous focal mucinosis. (05 Mar 2000) |
| equivalent focal length | <microscopy> The focal length of the simple lens that has the same power as the compound lens. The stated focal lengths of microscope objectives are the equivalent focal length since their front and back focal lengths are very different. (05 Aug 1998) |
| focal | Limited to one specific area. (16 Dec 1997) |
| focal adhesion | <cell biology> Areas of close apposition and thus presumably anchorage points, of the plasma membrane of a fibroblast (for example) to the substratum over which it is moving. Usually 1m x 0.2 m with the long axis parallel to the direction of movement, always associated with a cytoplasmic microfilament bundle that is attached via several proteins to the plasma membrane at an area of high protein concentration (this is noticeably electron dense in electron micrographs). Focal adhesions tend to be characteristic of slow moving cells. (18 Nov 1997) |
| focal amyloidosis | A localised form of amyloidosis in which amyloid occurs as masses or nodules beneath the skin or mucous membranes, e.g., in the larynx. Synonym: amyloid tumour, focal amyloidosis. (05 Mar 2000) |
| focal and segmental hyalinosis | <nephrology> A kidney disorder that results in fibrosis and scarring in the kidney glomerulus. The cause is unknown but some cases can result from reflux nephropathy. The clinical manifestation of this kidney disorder is nephrotic syndrome. Symptoms include weight gain, swelling, hypertension and foamy urine. High blood cholesterol and triglyceride levels are also seen with this disorder. Treatment has included the use of corticosteroids and immunosuppressives. Antihypertensive agents and diuretics may also be necessary. Over one-half will develop chronic renal failure within 10 years of diagnosis. (27 Sep 1997) |
| focal appendicitis | Acute appendicitis involving only part of the appendix, sometimes at the site of, or distal to, an obstruction of the lumen. (05 Mar 2000) |