This section is from the book "Applied Anatomy: The Construction Of The Human Body", by Gwilym G. Davis. Also available from Amazon: Applied anatomy: The construction of the human body.
The female pelvic organs are so often the subject of operative procedures that an exact knowledge of the relations of the uterus, vagina, ovaries, Fallopian tubes, round and broad ligaments, and ureters is of great importance.
The normal unimpregnated uterus is approximately 7.5 cm. (3 in.) long, 5 cm. (2 in.) broad, and 2.5 cm. (1 in.) thick. It consists of a fundus, body, and neck. Its fundus is that part above a line joining the two openings of the Fallopian tubes at the cornua. The neck of the uterus or cervix embraces 2.5 cm. (1 in.) of its lower portion. Between the neck and fundus is the body. The cavity of the uterus is small, its anterior and posterior walls being almost in contact, while laterally it extends toward the Fallopian tube openings. The opening through the cervix is the cervical canal; it opens into the vagina by the external os and into the uterus by the internal os; it is round in shape. The external os in the nullipara is round but in those who have borne children it is a transverse slit. The cervical canal is narrowed at both the internal os and the external os while it is larger between; hence in passing instruments into the uterus they traverse with difficulty the external os and the internal os but pass readily between the two and into the uterine cavity beyond.
The cervix enters the upper end of the vagina in its anterior wall and presents downward and backward (Fig. 458). Its posterior lip is longer than the anterior.
The uterus is most firmly fixed to the vagina and its upper portion is the most movable. Lying between the bladder anteriorly and intestines and rectum posteriorly its position varies with the condition of those organs. Normally it inclines anteriorly (anteversion). It lies in contact with the bladder, no intestines intervening. With an empty bladder it may point almost horizontally just above the top of the symphysis pubis, the external os being almost at the same level. As the bladder distends and the rectum becomes empty the fundus rises more and more until the axis of the uterus may coincide with that of the vagina, or even pass beyond; and then it is said to be retroverted. The uterus is normally almost straight or slightly bent forward. As the result of disease it becomes more or less sharply bent at the region of the internal os either forward or backward. It is then said to be anteflexed or retroflexed. When retroflexed the fundus can frequently be felt as a round hard mass behind the upper posterior portion of the vagina.
In addition to being attached to the vagina the uterus has certain folds or ligaments which pass from it to the surrounding parts. Anteriorly the peritoneum is reflected from the uterus at the level of the internal os to the bladder, forming the uterovesical fold. Posteriorly the peritoneum descends from the uterus over the posterior surface of the upper portion of the vagina for 1/2 or 2 cm. (1/2 in.) and thence onto the rectum constituting the rectovaginal or recto-uterine fold. The deep pouch so formed is called Douglas's pouch. On each side are three ligaments;
Fig. 458. - Lateral view of the interior of the female pelvis.
the broad ligament is the largest and most important. The two broad ligaments and uterus form a diaphragm which extends from one side of the pelvis directly across to the other, thus dividing it into anterior and posterior compartments. On the side of the uterus the broad ligament extends from the round ligament and Fallopian tube above down to below the level of the internal os. The anterior layer blends with the uterovesical fold at the level of the internal os, while the posterior goes to the bottom of the pouch of Douglas. It passes outward to be attached to the sides of the pelvis from the external iliac vein above down to the floor of the pelvis. Between the two peritoneal layers of the broad ligament at its top is the Fallopian tube, a little lower on the posterior surface is the ovary, going to the ovary are the ovarian vessels; lower still is the round ligament; and running in the base of the broad ligament are the uterine artery and ureter. At its pelvic attachment the broad ligament widens out, having the round ligament as its anterior edge and the infundibulopelvic or suspensory ligament of the ovary as its posterior edge. This latter runs not to the uterus but to the fimbriated extremity of the Fallopian tube and ovary and contains the ovarian vessels. A little posterior is the uterosacral ligament (recto-uterine); it runs from the uterus backward and contains muscular and fibrous tissue, the muscular tissue goes to the rectal wall while the fibrous goes to be attached to the second and third sacral vertebrae. This ligament on each side forms the outer border of Douglas's pouch.
Contained in the broad ligament between the Fallopian tube and ovary can be seen the remains of the parovarium or organ of Rosenmuller (page 453) and Gartner's duct. A little farther in are the remains of the paroophoron not clearly-visible to the unaided eye.
The round ligament leaves the cornu of the uterus just below and anterior to the Fallopian tube, and passes outward, forward, and slightly upward to reach the internal inguinal ring and canal through which it passes to end in the subcutaneous tissue and skin of the labium majus. Owing to the ovary and Fallopian tube falling backward the round ligament is seen as a distinct cord passing to the sides of the pelvis. It receives a branch from the deep epigastric artery.