| focal illumination | Illumination in which a beam of light is directed diagonally to an object so that it is brilliantly illuminated while the surrounding area is in shadow. Synonym: lateral illumination, oblique illumination. Kohler illumination, a method of illumination of microscopic objects in which the image of the light source is focused on the substage condenser diaphragm and the diaphragm of the light source is focused in the same plane with the object to be observed; maximises both the brightness and uniformity of the illuminated field. (05 Mar 2000) |
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| lateral illumination | Illumination in which a beam of light is directed diagonally to an object so that it is brilliantly illuminated while the surrounding area is in shadow. Synonym: lateral illumination, oblique illumination. Kohler illumination, a method of illumination of microscopic objects in which the image of the light source is focused on the substage condenser diaphragm and the diaphragm of the light source is focused in the same plane with the object to be observed; maximises both the brightness and uniformity of the illuminated field. (05 Mar 2000) |
| annular | <dermatology> Arranged in or forming a ring. (09 Oct 1997) |
| annular band | The strands of amniotic tissue adherent to the embryo or foetus; they may cause constriction of embryonic limbs. See: congenital amputation. Synonym: amniotic adhesions, annular band, constriction ring, Simonart's bands, Simonart's ligaments, Simonart's threads, Streeter's bands. (05 Mar 2000) |
| annular cartilage | <anatomy> The lower most of the laryngeal cartilages, may be palpated just below the thyroid prominence Adjacent the cricoid cartilage and the first tracheal ring is the cricothyroid membrane, a site used for rapid emergency airway access (cricothyroidotomy). (13 Nov 1997) |
| annular cataract | Congenital cataract in which a central white membrane replaces the nucleus. Synonym: disk-shaped cataract, life-belt cataract, umbilicated cataract. (05 Mar 2000) |
| annular ligament | <anatomy> One of a number of ligament's encircling various parts; the principal annular ligament's are those of the stapes, radius, and trachea. See: annular ligament of the radius, annular ligament of the stapes, annular ligaments of the trachea. Synonym: ligamentum annulare, orbicular ligament. (05 Mar 2000) |
| annular ligament of the radius | The ligament that encircles and holds the head of the radius in the radial notch of the ulna, forming the proximal radioulnar joint and enabling pronation/supination of forearm; receives the radial collateral ligament of the elbow. Synonym: ligamentum annulare radii, ligamentum orbiculare radii, orbicular ligament of radius. (05 Mar 2000) |
| annular ligament of the stapes | A ring of elastic fibres that attaches the base of the stapes to the margin of the fenestra vestibuli. Synonym: ligamentum annulare stapedis. (05 Mar 2000) |
| annular ligaments of the trachea | The fibrous membranes that connect adjacent tracheal cartilages. Synonym: ligamenta annularia trachealia, ligamenta trachealia. (05 Mar 2000) |
| annular lipid | The layer(s) of lipid bound to and/or surrounding an integral membrane protein. (05 Mar 2000) |
| annular pancreas | A rare condition where a ring of pancreatic tissue that forms around the duodenum causing partial or complete obstruction of the duodenum. A complete duodenal obstruction may be detected in the newborn although partial obstructions may not be detected well into adulthood. Nausea and vomiting are common symptoms. Diagnosis is via upper GI series, abdominal CT scanning or endoscopy. Treatment is surgical. Complications include peptic ulcer disease and perforation. (27 Sep 1997) |
| annular part of fibrous digital sheath | One of the two circular fibrous bands of the fibrous sheaths of the fingers and toes attached to the shaft of the proximal and middle phalanges. Synonym: pars annularis vaginae fibrosae, annular pulley, annulus of fibrous sheath, ligamentum annulare digitorum. (05 Mar 2000) |
| annular placenta | A placenta in the form of a band encircling the interior of the uterus. Synonym: zonary placenta. (05 Mar 2000) |
| annular plexus | A nerve plexus near the corneoscleral junction from which myelinated and unmyelinated nerves pass to the cornea. Synonym: plexus annularis. (05 Mar 2000) |