part of part_of part of part_of continuous_with continuous with connects connects cervix uterine cervix cervix uterine cervix 子宫颈(cervix) 子宫颈(uterine cervix) vagina ectocervix cervical os external cervical os FMA:76836 NCIT:C32491 Opening of uterine cervix into the vagina. The external orifice of the uterus (or ostium of uterus, or external os) is a small, depressed, somewhat circular aperture on the rounded extremity of the vaginal portion of the cervix. Through this aperture, the cervical cavity communicates with that of the vagina. The external orifice is bounded by two lips, an anterior and a posterior. The anterior is shorter and thicker, though it projects lower than the posterior because of the slope of the cervix. Normally, both lips are in contact with the posterior vaginal wall. Prior to pregnancy, the external orifice has a rounded shape when viewed through the vaginal canal (as through a speculum). Following parturition, the orifice takes on an appearance more like a transverse slit or is 'H-shaped'[Wikipedia:External_orifice_of_the_uterus]. UBERON:0013760 UMLS:C1512165 external os external os of uterus ostium of uterus ostium uteri uberon