| 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) |
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| 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) |
| annular pulley | 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 scleritis | An often protracted inflammation of the anterior portion of the sclera, forming a ring around the corneoscleral limbus. (05 Mar 2000) |
| annular scotoma | A circular scotoma surrounding the centre of the field of vision. See: ring scotoma. (05 Mar 2000) |
| annular sphincter | A short thickening of circular muscular fibres, similar to a ring; a ring-shaped sphincter as opposed to a segmental sphincter. (05 Mar 2000) |
| annular staphyloma | A staphyloma extending around the periphery of the cornea. (05 Mar 2000) |
| annular stop | <microscopy> The opaque ring-shaped stop with a small central opening usually placed in the objective back focal plane to provide dispersion staining. (05 Aug 1998) |