Ostium

The Student's Medical Dictionary · 1896 · p. 469

(osr -te-um) [L.]. A mouth or aperture. O. abdominale, the orifice of the oviduct communicating with the peritoneal cavity. O. internum, the uterine opening of the oviduct. O. pharyngeum, the pharyngeal opening of the Eustachian tube. O. tympani cum, the tympanic opening of the Eustachian tube. O. vaginae, the external orifice of the vagina. 469