| cricopharyngeal part of inferior pharyngeal constrictor | See: inferior constrictor muscle of pharynx. Synonym: pars cricopharyngea musculi constrictoris pharyngis inferioris. (05 Mar 2000) |
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| sphincter of the pharyngeal isthmus | A constant band of the superior pharyngeal constrictor muscle which sweeps posteriorly from the anterolateral part of the superior surface of the palatine aponeurosis. It creates a visible ridge when the superior constrictor is contracted, meeting the elevated soft palate to seal off the pharyngeal isthmus during swallowing. Synonym: pharyngeal ridge, sphincter of the pharyngeal isthmus, velopharyngeal sphincter. (05 Mar 2000) |
| syndrome, third and fourth pharyngeal pouch | See syndrome, digeorge. (12 Dec 1998) |
| third and fourth pharyngeal pouch syndrome | <syndrome> Also called the digeorge syndrome (dgs), this disorder is characterised by (1) low blood calcium levels (hypocalcaemia) due to underdevelopment (hypoplasia) of the parathyroid glands which control calcium; (2) underdevelopment (hypoplasia) of the thymus, an organ behind the breastbone in which lymphocytes mature and multiply; and (3) defects of the heart involving the outflow tracts more than from the heart. most cases of dgs are due to a microdeletion in chromosome band 22q11.2. A small number of cases have defects in other chromosomes, notably 10p13. Named after the american paediatric endocrinologist angelo digeorge. Another name for dgs is hypoplasia of the thymus and parathyroids. (12 Dec 1998) |
| thyropharyngeal part of inferior pharyngeal constrictor muscle | thyropharyngeal part of inferior pharyngeal constrictor muscle |
| lateral pharyngeal space | That part of the peripharyngeum spatium located at the sides of the pharynx. Synonym: spatium lateropharyngeum. (05 Mar 2000) |
| abdominal ring | The opening in the transversalis fascia through which the ductus deferens (or round ligament in the female) and gonadal vessels enter the inguinal canal. Located midway between anterior superior iliac spine and pubic tubercle, it is bounded medially by the lateral umbilical ligament (inferior epigastric vessels) and inferiorly by the inguinal ligament. Indirect inguinal hernias exit the abdominal cavity via the deep inguinal ring Synonym: annulus inguinalis profundus, abdominal ring, annulus abdominalis, internal inguinal ring. (05 Mar 2000) |
| amnion ring | The ring formed by the attachment of the amnion to the umbilical cord at its point of emergence from the umbilicus. (05 Mar 2000) |
| annuloplasty ring | The dilated annulus is sutured, often to a prosthetic ring, thereby reducing it to its normal systolic size. (05 Mar 2000) |
| anterior limiting ring | The periphery of the cornea marking the termination of Descemet's membrane and the anterior border of the trabecular meshwork; an important landmark in gonioscopy. Synonym: Schwalbe's ring. (05 Mar 2000) |
| Balbani ring | An extremely large puff at a band of a polytene chromosome. (05 Mar 2000) |
| Balbiani ring | <cell biology, genetics> The largest puffs seen on the polytene chromosomes of Diptera are called Balbiani rings after the nineteenth century microscopist who first described polytene chromosomes. (18 Nov 1997) |
| Bandl's ring | A constriction located at the junction of the thinned lower uterine segment with the thick retracted upper uterine segment, resulting from obstructed labour; this is one of the classic signs of threatened rupture of the uterus. Synonym: Bandl's ring, Baudelocque's uterine circle, Scanzoni's second os. (05 Mar 2000) |
| benzene ring | The closed-chain arrangement of the carbon and hydrogen atoms in the benzene molecule. See: cyclic compound. (05 Mar 2000) |
| Bickel's ring | The broken ring of lymphoid tissue, formed of the lingual, faucial, and pharyngeal tonsils. Synonym: Bickel's ring, tonsillar ring, Waldeyer's throat ring. (05 Mar 2000) |