| annulus tendineus communis | A fibrous ring that surrounds the optic canal and the medial part of the superior orbital fissure; it gives origin to the four rectus muscles of the eye and is partially fused with the sheath of the optic nerve. Synonym: annulus tendineus communis, Zinn's ligament, Zinn's ring, Zinn's tendon. (05 Mar 2000) |
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| annulus tympanicus | In the foetus, a more or less complete bony ring at the medial end of the cartilaginous external acoustic meatus, to which is attached the tympanic membrane. Synonym: annulus tympanicus, tympanic bone. (05 Mar 2000) |
| annulus umbilicalis | An opening in the linea alba through which pass the umbilical vessels in the foetus; in young embryos it is relatively nearer to the pubis, but gradually ascends to the centre of the abdomen; it is closed in the adult, its site being indicated by the umbilicus or navel. Synonym: annulus umbilicalis, canalis umbilicalis. (05 Mar 2000) |
| annulus urethralis | The complete collar of smooth muscle cells of the neck of the urinary bladder which extend distally to surround the preprostatic sportion of the male urethra. There is not a comparable structure in the neck of the femoral bladder; the internal urethral sphincter may exist to prevent reflux of semen into bladder. Synonym: annulus urethralis, internal urethral sphincter, musculus sphincter vesicae, preprostate urethral sphincter, proximal urethral sphincter, sphincter muscle of urinary bladder. (05 Mar 2000) |
| Vieussens' annulus | A muscular ring surrounding the fossa ovalis in the wall of the right atrium of the heart. Synonym: annulus ovalis, margin of fossa ovalis, Vieussens' annulus, Vieussens' isthmus, Vieussens' limbus, Vieussens' ring. (05 Mar 2000) |
| periseptal annulus | Organelle associated with cell division in gram-negative bacteria. There are two circumferential zones of cell envelope in which membranous elements of the envelope are closely associated with murein. The annuli appear early in division and in the region between them, the periseptal compartment, the division septum is formed. (18 Nov 1997) |
| Haller's annulus | A doubling of the thoracic duct for part of its course through the thorax. Synonym: Haller's annulus. (05 Mar 2000) |
| arcus palmaris superficialis | superficial palmar (arterial) arch |
| arcus venosus palmaris superficialis | The venous arch accompanying the superficial palmar arterial arch it consists usually of paired venae comitantes and is drained by the superficial ulnar and radial veins. Synonym: arcus venosus palmaris superficialis. (05 Mar 2000) |
| arcus volaris superficialis | superficial palmar (arterial) arch |
| arteria brachialis superficialis | <anatomy, artery> An occasional variation in which the brachial artery lies superficial to the median nerve in the arm. Synonym: arteria brachialis superficialis. (05 Mar 2000) |
| arteria cervicalis superficialis | <anatomy, artery> Origin, branch of thyrocervical trunk, running with spinal accessory nerve deep to trapezius muscle. See: superficial branch of the transverse cervical artery. Synonym: arteria cervicalis superficialis. (05 Mar 2000) |
| arteria circumflexa iliaca superficialis | <anatomy, artery> Origin, femoral; distribution, inguinal lymph nodes and integument of that region; sartorius, and tensor fasciae latae muscles; anastomoses, deep circumflex iliac. Synonym: arteria circumflexa iliaca superficialis. (05 Mar 2000) |
| arteria epigastrica superficialis | <anatomy, artery> Origin, femoral; distribution, inguinal nodes and integument of lower abdomen; anastomoses, inferior epigastric, superficial circumflex iliac and external pudendal. Synonym: arteria epigastrica superficialis. (05 Mar 2000) |
| arteria temporalis superficialis | <anatomy, artery> Origin, a terminal branch of the external carotid (with maxillary artery); branches, transverse facial, middle temporal, orbital, parotid, anterior auricular, frontal, and parietal. Synonym: arteria temporalis superficialis. (05 Mar 2000) |