INTRODUCTION TO WOMEN'S IMAGING (FEMALE PELVIS IMAGING)
The uterus is a pear-shaped organ located in the female pelvis between the urinary bladder anteriorly and the rectum posteriorly (Figs. 10.1 and 10.2). The average dimensions are approximately 8 cm long, 5 cm across, and 4 cm thick, with an average volume between 80 and 200 mL. The uterus is divided into 3 main parts: the fundus, body, and cervix.
Sagittal view of the female pelvis, demonstrating relative positions of the bladder, uterus, and rectum.
Illustration of the uterus, adnexal structures, and upper vagina.
Blood is provided to the uterus by the ovarian and uterine arteries, the latter of which arise from the anterior division of the internal iliac artery. The uterine artery occasionally gives off the vaginal artery (although this is usually a separate branch of the internal iliac artery), which supplies the upper vagina, and the arcuate arteries, which surround the uterus. It then further branches into the radial arteries, which penetrate the myometrium to provide blood to all layers, including the endometrium.
Once these vessels reach the endometrial level, they branch into the basal arteries and spiral arteries, which support the specialized functions of each layer. The basal arteries are not responsive to hormones; they support the basal endometrial layer, which provides the proliferative cells for endometrial growth. The spiral arteries supply the functionalis layer and are uniquely sensitive to steroid hormones. In ovulatory cycles in which pregnancy does not occur, menses results following constriction of these terminal arteries, causing endometrial breakdown with desquamation of the glands and stroma.
The ovaries are the female pelvic reproductive organs that house the ova and are responsible for the production of sex hormones. They are paired organs located on either side of the uterus within the broad ligament below the uterine (fallopian) tubes. The ovary is within the ovarian fossa, a space that is bound by the external iliac vessels, obliterated umbilical artery, and ureter. The ovaries are responsible for housing and releasing ova, or eggs, necessary for reproduction. At birth, a female has approximately 1 to 2 million ova, but only 300 of these eggs will ever become mature and be released for the purpose of fertilization.
The ovaries are small, oval-shaped, and grayish in color, with an uneven surface. The actual size of an ovary depends on a woman's age and hormonal status; the ovaries, covered by a modified peritoneum, are approximately 3 to 5 cm in length during childbearing years and become much smaller and then atrophic once menopause occurs. A cross section of the ovary reveals ...