Human Anatomy Part 1 - K. A. Dyubenko, A. K. Kolomiytsev, Yu. B. Chaykovsky 2002

Special Section
Reproductive Systems, systemata genitalia — Female Reproductive System, systema genitale femininum
Internal Female Genital Organs, organa genitalia feminina interna — Uterus — Structure of the Uterus

The wall of the Uterus consists of three layers (see Fig. 328):

- the inner layer, the mucous membrane, tunica mucosa [endometrium];

- the middle, thickest layer, the muscular coat, tunica muscularis [myometrium], which comprises three strata: an inner longitudinal layer, a middle circular layer, and an outer longitudinal layer;

- the outer layer, the serous coat, tunica serosa [perimetrium].

The mucous membrane, tunica mucosa, is lined with a simple columnar epithelium. It contains numerous uterine glands, gll. uterinae, which are classified morphologically as simple tubular glands. In mature women, the uterine mucosa undergoes cyclic changes associated with the Menstrual cycle (menstruation). During menstruation, the upper (functional) layer of the mucosa undergoes shedding (desquamation). Following menstruation, the mucous membrane regenerates rapidly.

The muscular coat, tunica muscularis, forms the bulk of the uterus. It consists of three layers of smooth Muscle fibers interweaving in various directions: an inner longitudinal layer, a middle circular layer, and an outer longitudinal layer. The middle layer is highly vascularized and is therefore designated as the stratum vasculosum.

The serous coat, the Peritoneum, covers the Cytology/practical/108.html">Fundus of the uterus as well as its anterior and posterior surfaces. Anteriorly, it covers the uterus down to the level of the cervix and reflects onto the Urinary Bladder, forming the vesicouterine pouch, excavatio vesicouterina. Posteriorly, the peritoneum lines the posterior surface of the uterus and the posterior fornix of the Vagina, then reflects onto the rectum to form the rectouterine pouch, excavatio rectouterina. Laterally, the peritoneum extends to the pelvic wall, forming the broad ligament of the uterus, lig. latum uteri, between the layers of which lie the parametrium, the uterine artery, the uterine venous plexus, and the nerve plexus. From the upper corners of the uterus, the round ligaments of the uterus, ligg. teres uteri, extend toward the deep inguinal ring. Traversing the Inguinal Canal, they terminate at the Pubic Symphysis. Additionally, the uterus is connected to the rectum by the rectouterine ligaments, ligg. rectouterini, and the corresponding Muscles situated within the peritoneal fold.

Ultrasonography of the uterus. Echography allows for the Determination of the uterine position within the lesser pelvis, including deviations to the right, to the left, or retroverted.

Posterior to the urinary bladder, the uterus is visualized; on longitudinal sonograms, it presents a characteristic pear-like (pyriform) shape, whereas on transverse scans, it appears ovoid. The internal architecture of the uterus is acoustically heterogeneous: the myometrium is homogeneous and echogenic in Structure, while the echo reflections from the endometrium vary depending on the phase of the menstrual cycle. Early in the cycle, the endometrium appears as a thin linear echostructure that thickens by the end of the cycle. In adult women, the dimensions of the uterine body range from 55 to 75 cm in width. The length of the uterine cervix averages 20-25 mm (B. I. Zybin, 1982).

Blood supply to the uterus is provided by the uterine artery, aa. uterinae (a branch of the internal iliac artery), and partially by the ovarian artery, aa. ovaricae (a branch of the Abdominal Aorta). Venous blood drains into the plexus uterinus, and subsequently via vv. uterinae and vv. ovaricae into the internal iliac Veins, iliacae internae.

Lymphatic drainage from the uterus occurs via several pathways: Lymphatic vessels draining the uterine tubes and Ovaries empty into regional Lymph Nodes. Lymphatic vessels draining the cervix and the upper third of the vagina empty into visceral and common iliac lymph nodes, as well as partially into the posterior rectal nodes. Lymphatic vessels from the uterine body, uterine tubes, and ovaries drain into the lumbar and sacral nodes.

Innervation of the uterus. The uterus is innervated by the sympathetic and parasympathetic Divisions of the Autonomic Nervous system. Sympathetic fibers arise from the inferior hypogastric plexus. Parasympathetic innervation is supplied by the pelvic splanchnic nerves, nn. pelvini splanchnici.