Anatomy, Abdomen and Pelvis: Uterus

Excerpt

The uterus, a hollow, pear-shaped organ, facilitates gestation, menstruation, and labor. On coronal section, the uterine cavity appears as an inverted triangle. Incomplete embryologic development may result in Müllerian anomalies, producing structural variants such as a uterine septum or uterine didelphys (double uterus). Positioned in the female pelvis, the uterus lies posterior to the bladder and anterior to the rectum. This organ consists of 4 anatomic segments arranged from superior to inferior: the fundus, a broad curved region where the fallopian tubes connect; the corpus, which begins below the level of the tubes and comprises the main uterine body; the isthmus, a narrowed segment at the lower uterine neck; and the cervix, which projects downward from the isthmus into the vagina (see Image. The Uterus).

Several ligaments stabilize the uterus, including the utero-ovarian, round, broad, cardinal, and uterosacral ligaments (see Image. Uterine Tubal Anatomy and Ligaments). Additional inferior support comes from the pelvic diaphragm, urogenital diaphragm, and perineal body. Uterine position varies among individuals. Common orientations include anteverted, retroverted, anteflexed, retroflexed, or midline, with possible rotation, particularly during pregnancy. In approximately 50% of women, the uterus adopts an anteflexed and anteverted orientation. A retroverted or retroflexed (or "tipped") uterus may contribute to pelvic pain, dyspareunia, mild urinary incontinence, infertility, and tampon insertion difficulties. During pregnancy, this orientation can lead to uterine incarceration.