Internal Organs: Uterus, Fallopian Tubes, Ovaries

By OBOS Anatomy & Menstruation Contributors | March 31, 2014

The non-pregnant uterus is about the size of a plum. It is located between the bladder, which is beneath the abdominal wall, and the rectum, which is near the backbone.

Its thick walls are made of some of the most powerful muscles in the body. The inner walls touch unless pushed apart by a growing fetus or an abnormal growth.

The top of the uterus is called the fundus. Extending outward and back from each side of the fundus are the two fallopian tubes (also called oviducts; literally, “egg tubes”). They are approximately four inches long and look like thin ram’s horns facing backward.

The connecting opening from the inside of the uterus to the fallopian tubes is as small as a fine needle. The outer end of each tube is fringed (fimbriated) and funnel-shaped. The wide end of the funnel wraps partway around the ovary but does not actually attach to it. The fallopian tubes are held in place by connective tissue.

The ovaries are organs about the size and shape of unshelled almonds, located on either side of and somewhat behind the uterus. They are about four or five inches below your waist and are held in place by connective tissue.

The ovaries have a two-fold function: to produce germ cells (eggs), and to produce sex hormones (estrogen, progesterone, testosterone, and many others). The functions of these hormones are only partly understood.

The small gap between the ovary and the end of the corresponding tube allows the egg to float freely in the abdominal cavity after it has been released from the ovary. The fingerlike ends (fimbria) of the fallopian tube sweep across the surface of the ovary and wave the egg into the tube after ovulation.

The uterus, fallopian tubes and ovaries are draped in peritoneum, the thin membrane that lines the inside of the abdominal cavity.