The ovaries are paired female gonads and the main female endocrine organs where oocyte maturation and sex hormone synthesis occur.

They are located on either side of the uterus in the ovarian fossa found on the lateral wall of the true pelvis at the level of the sacroiliac joint under the bifurcation of the common iliac artery (under the external iliac artery and in front of the internal iliac artery and ureter).

The ovaries are intraperitoneal organs, as they are covered by the peritoneum from all sides, and they are mobile.

Superior to each ovary is located the infundibulum of the Fallopian tube. The ovaries are situated laterally to the uterus on each side and are connected to it with the help of the proper ovarian ligament (uteroovarian ligament), as well as with the broad ligament of the uterus and with its mesovarium.

The proper ovarian ligament connects the inferior pole of the ovary with the uterus below the uterine horn, which is the connection site of the body of the uterus and the Fallopian tube. The proper ovarian ligament lies within the broad ligament of the uterus.

The mesovarium is a double layer of the peritoneum and a part of the broad ligament. It extends from the posterior surface of the broad ligament to the anterior margin and anterior surface of the ovary.

Both mentioned ligaments fix the ovary in its place, but there is another ligament. It is the suspensory ligament of the ovary that extends between the wall of the pelvis and the superior pole of the ovary. The ligament contains the ovarian artery and ovarian vein, and ovarian plexus.

Each ovary has the size and shape of a bean or an almond. The normal ovary of an adult woman is approximately 1 - 2 inches (2.5 - 5 cm) in length, 0.6 - 1.2 inches (1.5 - 3 cm) in width and 0.3 - 0.6 inches (0.8 - 1.5 cm) thick (the average size is 3.5 x 2.5 x 1.5 cm). They each weigh around 0.1 to 0.3 ounces or 4 - 8 grams.

The volume of the ovary changes during the lifetime. Young girls have smaller ovaries compared to an adult women. Women who have given birth tend to have larger ovaries than those who have not. The volume and size decrease with age.

Each ovary has two poles, two margins, and two surfaces.

The poles or extremities of the ovary are as follows:

Each ovary has two margins:

Anterior margin (mesovarian margin) - attached to the posterior surface of the mesovarium; in the middle of the margin is the hilum of the ovary through which blood vessels, nerves and lymphatics enter or exit the ovary;
Posterior margin (free margin) - this ovarian margin is rounded and convex.

Also, each ovary has two external surfaces, known as the lateral surface and medial surface.

The external surfaces of the ovary are covered by the tunica albuginea.

Underneath the tunica albuginea each ovary consists of two parts:

Cortex - the outermost and largest part; consists of parenchyma of the ovary where follicles in various stages of differentiation are located in between the connective tissue;
Medulla - the innermost part, located in the center of each ovary; contains connective tissue, blood vessels and lymphatics, as well as nerves of the ovaries.

There are two primary functions of the ovaries, and they are:

Oogenesis - differentiation, and release of oocytes; therefore, ovaries provide the reproductive function;
Production and secretion of sex hormones - the ovaries create and release such hormones as progesterone, estrogen, also a small number of androgens, for example, testosterone.

NOTE: a newborn female has around 50 000 - 80 000 follicles. When puberty is reached at about 11 - 13 years old, the follicles begin to maturate. Approximately 500 follicles mature during a lifetime. Each menstrual cycle is approximately 28 days long, and in each cycle mature and ovulate one, rarely two follicles. The ovaries function until about 45 - 50 years of age.

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Ovaries