Anatomy

The uterus is a muscular, hollow, pear-shaped organ situated in the midpelvis between the sacrum and the pubic symphysis. Before child-bearing, it is about 3 in. (7.5 cm) long, 2 in. (5 cm) wide, and 1 in. ( 2.5 cm) thick. Its upper surface is covered by the perimetrium, and it is supported by the pelvic diaphragm supplemented by the two broad ligaments, two round ligaments, and two uterosacral ligaments. It is usually tilted forward over the top of the urinary bladder. The upper portion of the uterus, between the openings of the fallopian tubes, is the fundus; the large central portion is the body; and the narrow lower end is the cervix, which projects into the vagina. The cavity of the uterus is widest in the fundus. The canal of the cervix is narrow, opens into the uterine cavity at the internal os, and into the vagina at the external os.

The wall of the uterus consists of the outer perimetrium, middle myometrium, and inner endometrium. The uterine and ovarian arteries supply blood to the uterus.

Positions

Anteflexion: The uterus bends forward. Anteversion: The fundus is displaced forward toward the pubis, while the cervix is tilted up toward the sacrum. Retroflexion: The uterus bends backward at the junction of the body and the cervix. Retroversion: The uterus inclines backward with retention of the normal curve; this position is the opposite of anteversion.