Anatomy of the uterus

Abstract 

The uterus is a pear-shaped organ made up of a fundus, body, isthmus and cervix. The fallopian tube enters at each superolateral angle, above which lies the fundus. The cervix is gripped by the vagina to form a supra-vaginal and a vaginal part. The uterine canal traverses the internal os and emerges as the external os at the vaginal vault. The uterine body is flexed on the cervix (anteflexion) while the whole uterus is tipped forward (anteversion). Variations of these positions, termed retroflexion and retroversion, may occur in normal anatomy as well as under pathological circumstances. The ureter has an important relationship to the uterus, lying above the lateral fornix, about 12 mm from the supravaginal cervix. Here it is crossed superiorly by the uterine vessels and is at risk of injury in pelvic surgery, especially hysterectomy. In the child, the cervix is twice the size of the uterine body, but at puberty the body enlarges to its adult proportions. The cervical os is circular, but becomes a transverse slit in the parous woman. The cervix is normally firm, but feels soft in pregnancy. The details of the arterial supply, venous drainage, lymphatic drainage, peritoneal coverings and anatomical relationships are described.

Keywords: anatomy, anteflexion, cervix, external os, fornix, fundus, internal os