Porth's Essentials of Pathophysiology, 4e

1034

Genitourinary and Reproductive Function

U N I T 1 1

Small bowel

Rectovaginal septum and uterosacral ligaments

Uterus

Cervix

Bladder

Vaginal rectal fascia

Rectum

Urethra

Intact perineum

Vagina

A

B

C

D

FIGURE 40-13. (A) Normal support of the uterus and vagina, (B) cystocele, (C) rectocele, and (D) uterine prolapse.

In the female anatomy, nature is faced with the prob- lems of supporting the pelvic viscera against the force of gravity and the increases in intra-abdominal pressure associated with coughing, sneezing, defecation, and laughing, while at the same time allowing for urination,

defecation, and normal reproductive tract function, especially the delivery of an infant. Relaxation of the pelvic outlet usually comes about because of overstretching of the perineal supporting tis- sues during pregnancy and childbirth or years of pro- longed straining with hard stools. Although the tissues are stretched only during these times, there may be no difficulty until later in life, such as in the fifth or sixth decade, when further loss of elasticity and muscle tone occurs. Even in a woman who has not borne children, the combination of aging and postmenopausal changes may give rise to problems related to relaxation of the pelvic support structures. The three most common con- ditions associated with this relaxation are cystocele, rectocele, and uterine prolapse. 36 These may occur sepa- rately or together. Cystocele is a herniation of the bladder into the vagina. It occurs when the normal muscle support for the bladder is weakened, and the bladder sags below the uterus. This causes the anterior vaginal wall to stretch and bulge downward, allowing the bladder to herniate into the vagina due to the force of grav- ity and pressures from coughing, lifting, or straining at stool (see Fig. 40-13B). The symptoms of cystocele include an annoying bearing-down sensation, difficulty

Bulbocavernosus Ischiocavernosus

Pubis

Gluteus maximus Transverse perineal

Femur

Ischial tuberosity

Levator ani

Anus External anal sphincter

FIGURE 40-14. Muscles of the pelvic floor (female perineum).