| annulus of fibrous 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) |
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| annulus ovalis | 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) |
| 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) |
| 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) |
| anterior canaliculus of chorda tympani | <anatomy> A canal in the petrotympanic or glaserian fissure, near its posterior edge, through which the chorda tympani nerve issues from the skull. Synonym: Civinini's canal, Huguier's canal, iter chordae anterius. (05 Mar 2000) |
| apertura tympanica canaliculi chordae tympani | The small canal opening found lateral to the pyramidal eminence in the posterior wall of the middle ear cavity from which the chorda tympani nerve emerges to pass anteriorly between the ossicles accompanied by a branch of the stylomastoid artery. Synonym: apertura tympanica canaliculi chordae tympani. (05 Mar 2000) |
| canaliculus chordae tympani | A canal leading from the facial canal to the tympanic cavity through which the chorda tympani nerve enters this cavity. Synonym: canaliculus chordae tympani, iter chordae posterius, small canal of chorda tympani. (05 Mar 2000) |
| ramus communicans cum chorda tympani | <anatomy, nerve> Terminal branch of chorda tympani joining the lingual nerve in the infratemporal fossa; conveys sensory fibres for taste from anterior two-thirds of tongue and presynaptic parasympathetic fibres destined for submandibular ganglion for innervation of submandibular and sublingual salivary glands. Synonym: ramus communicans cum chorda tympani. (05 Mar 2000) |
| paries caroticus cavi tympani | It contains the carotid canal and the opening of the auditory tube. Synonym: paries caroticus cavi tympani, anterior wall of middle ear, carotid wall of middle ear. (05 Mar 2000) |
| paries jugularis cavi tympani | The floor of the tympanic cavity; a thin plate of bone separating the tympanic cavity from the jugular fossa. Synonym: paries jugularis cavi tympani, fundus tympani, inferior wall of tympanic cavity, jugular wall of middle ear. (05 Mar 2000) |