SPHINCTER

(Lat.), n. m. Sfi2n2kt'u6r(ar). Gen., -er'os (-is). Gr., iycT>jp. Fr., s. Ger., Schlie muskel. An annular muscle which constricts or closes a natural orifice: especially the s. ani. [L, 343.] Circular s. of the anus. See S. ani intern us. Laryngeal s. See S. laryngis. S. ani (cutaneus, seu extern us). Fr., s. anal (ou de Vanus). Ger., Afterschlie er. A flat azygous oval muscle surrounding the anus. It arises from the tip and posterior surface of the coccyx and blends anteriorly with the skin of the perinseum and the perineal fascia and muscles. [L, 31, 333.] S. ani intern us. Ger., innerer Afterschlie er. A thickened bundle of the circular muscular fibres of the rectum about an inch above the anus. [L.] S. ani snperficialis. See S. ani extern us.S. ani tertius. An inconstant thickening of the circular fibres of the rectum a short distance above the s. ani intern us. (L.] S. coccygio-cutane (Fr.). See S. ani extern us. S. cuiini. See S. vaginae. S. de la bouche (Fr.). See ORBICULARIS or is. S. de Nelaton (Fr.). See S. ani tertius. S. gulae. 1. The conetrictores pharyngis regarded as a single structure. 2. Of Cowper, the inferior constrictor of the pharynx, [a, 46.] S. ilei. See Ileo-ccecal VALVE. S. irid is (major). Circular muscular fibres of the iris surrounding the pupil. [L, 332.] S. irid is minor. Circular muscular fibres at the periphery of the iris. [L, 332.] S. labiorum. See ORBICULARIS or is. S. laryngis. See COMPRESSOR laryngis. S. oculi. See ORBICULARIS palpebra rum. S. cesophageus. See FORAMEN cesophageum.S. of the uterus. A special re-enforcement of the circular muscular fibres surrounding the os uteri internum. [a, 22.] S. or is. See ORBICULARIS orj's.S. or is extern us. See STRATUM externum orbicularis or is.S. or is intern us. See STRATUM internum orbicularis or is. S. palpebra rum. See OnBICULARIS palpebra rum. S. pharyngolaryngeus. The inferior constrictor of the phaynx, the cricothyreoidei, and the thyreoidei trans vers i. [L, 332.] S. prostatae. See S. urethrce prostatic us. S. pupillae. See S. irid is (major). S. pylori. A ring-like bundle of muscular fibres surrounding the pylorus. [L.] S. superior (tertius). See S. ani tertius. S, urethrae. See STRATUM mv.iculare circulare urethrce. S. urethras prostatic us. Muscular fibres surrounding the anterior portion of the prostate gland. [L, 31, 332.] S. vaginae. Ger., Scfmiirmuskel der Scheide. A circular bundle of voluntary muscular fibres surrounding the lower extremity of the vagina and urethra, and serving to close those canals. See also CONSTRICTOR cunni. S. vaginae profunclus. See CONSTRICTOR cunni pro fundus. S. ventriculi. See PYLORUS. S. vesicae. Circular muscular fibres of the bladder nearest the commencement of the urethra. [L.] S. vesicae extern us. See S. urethrce prostatic us. S. vesicae intern us. 1. See S. vesicce. 2. The portion of the muscular coat of the prostate gland nearest the bladder. [L, 31.] Superficial s. of the anus. See S. ani extern us. [s. 515]