6. The Adult Female Uterus

  1. Uterine anatomy: the uterus is a thick-walled, pear-shaped organ, 7.0 x 5.0 x 2.5 cm, consisting of an upper body (corpus) with its rounded, dome-shaped top or fundus; and a narrow, cylindrical neck or cervix whose terminal portion projects into the vagina as the portio vaginalis. The part between body and cervix is the isthmus. The walls consist of 3 layers
    1. PERIMETRIUM: a very thin outer serosa which is the peritoneal layer of the broad ligament and is firmly attached to the underlying muscularis
    2. MYOMETRIUM (MUSCLE): a thick middle smooth muscle layer about 15 mm thick having 3 layers of muscle
      1. Stratum subvasculare: inner longitudinal muscle layer
      2. Stratum vasculare: middle circular or spiral layer forming the bulk of the muscularis with many large blood vessels, especially veins
      3. Stratum supravasculare: outer, thin layer with circular and longitudinal fibers
    3. ENDOMETRIUM: thin inner layer lined by simple columnar epithelium with many tubular glands. There is no submucosa, and the mucosa is closely attached to the myometrium
      1. During secretory phase of menstrual cycle, 3 layers of endometrium can be seen
        1. Compact layer (compacta): thin, narrow superficial layer of densely packed stromal cells around the straight necks of glands. Little edema here
        2. Spongy layer (spongiosa) makes up the bulk of the endometrium composed of edematous stroma with dilated, tortuous bodies of glands
        3. Basal layer (basalis): deepest layer, relatively thin and narrow, containing the blind ends of glands. The latter undergo little or no chang This layer has its own blood supply and is not lost at menstruation or at parturition
        4. Functionalis layer consists of layers a and Disintegrates and is shed at menstruation and parturition
    4. BLOOD SUPPLY: via the uterine artery (usually a branch of the internal iliac but may arise as a common trunk with the vaginal or with the middle rectal artery). Ends as the ovarian branch which anastomoses with the ovarian artery. In addition, a variable number of branches go to the cervix, upper vagina, medial part of uterine tube (tubal branch), the round ligament of the uterus and the ligament of the ovary. Blood is returned via a venous plexus that follows the uterine artery
    5. NERVE SUPPLY: receives autonomic and sensory fibers via the uterovaginal plexuses which run along the uterine artery
      1. The uterus is painless to most stimuli, but pain may be felt when the cervix is grasped with a forceps or is dilate These nerve fibers may ascend and enter the spinal cord via the lumbar splanchnic nerves
      1. From fundus and upper body drain into lumbar (or aortic) nodes
      2. From lower body drain into external iliac nodes
      3. From cervix drain into external iliac, internal iliac, and sacral nodes
      4. From area near the uterine tubes, drainage follows the round ligament and may drain into superficial inguinal nodes

the adult female uterus: image #1