106. Development of The Upper and Lower Portions of The Female Genital Tract

  1. The upper portion of the genital tract
    1. AFTER FORMATION OF THE UTEROVAGINAL CANAL, the segment of each paramesonephric (m?llerian) duct, which is cranial to the junction of the inguinal ligament and the urogenital cord, becomes the uterine (fallopian) tubes
      1. The cranial opening of the paramesonephric duct, which is open to the peritoneal cavity, becomes the fimbriae of the uterine tube
      2. The uterine tube eventually moves caudally and becomes horizontal
    2. THE MESONEPHRIC (WOLFFIAN) DUCTS REGRESS almost completely, leaving only a short segment connected with the mesonephric tubes adjacent to the ovary which persists as the epo?phoron or Rosenm?ller's body
      1. Other mesonephric tubules caudal to the ovary form the paroophoron
    3. AFTER THE MESONEPHRIC DUCT REGRESSES, the diaphragmatic ligament is attached directly to the ovary at its cephalic pole and becomes the suspensory ligament of the ovary
      1. The inguinal ligament, which is also attached to the ovary but at its caudal pole, becomes the proper ligament of the ovary
    4. THE MESONEPHRIC BODY flattens and atrophies beginning in month 3, and only a vestige persists between the urogenital and the mesonephric mesenteries. These 3 structures together form the mesosalpinx, which connects the urogenital cord and the uterine tube to the abdominal wall
      1. The mesovarium is thus attached definitively to the inside of the mesosalpinx and is also continuous caudally with the mesometrium, forming with it, the broad ligament
  2. The lower portion of the genital tract
    1. TWO REGIONS CAN BE DISTINGUISHED on either side of the openings of the mesonephric and paramesonephric ducts, in the urogenital sinus
      1. The urinary or cranial region (described with the urinary system)
      2. The genital or caudal region, which in turn, has 2 major parts
        1. The interior or deep vertical portion is the pelvic portion of the urogenital sinus
          1. In the female fetus, its cranial end contains the urethral orifice ventrally, and the termination of the vaginal epithelial plate dorsally
          2. The pelvic portion of the urogenital sinus becomes less deep, bringing to the surface the urethral orifice (or urinary meatus) and the hymen
          3. The pelvic portion is finally incorporated with the phallic portion, to form with it the vestibule, which is surrounded by the external genital organs
        2. The superficial or horizontal portion is the phallic portion of the urogenital sinus
          1. It is bordered by the genital tubercle, cranially; and the urogenital membrane, caudally
          2. After resorption of the membrane in week 9, the phallic portion of the urogenital sinus becomes open to the exterior
      3. Differentiation of the genital portion of the urogenital sinus in the female follows that of the urogenital excretory system and begins in month 3, paralleling the formation of the vagina and the external genital organs

development of the upper and lower portions of the female genital tract: image #1