Pelvic floor

The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus, and associated connective tissue which span the area underneath the pelvis.

The pelvic cavity of the true pelvis has the pelvic floor as its inferior border (and the pelvic brim as its superior border.)

Some sources do not consider the "pelvic floor" and "pelvic diaphragm" to be identical, with the "diaphragm" consisting of only the levator ani and coccygeus, while the "floor" also includes the perineal membrane and deep perineal pouch. However, other sources include the fascia as part of the diaphragm. In practice, the two terms are often used interchangeably.

Inferiorly, the pelvic floor extends into the anal triangle.

Function
It is important in providing support for pelvic viscera (organs), e.g. the bladder, intestines, the uterus (in females), and in maintenance of continence as part of the urinary and anal sphincters.

Clinical significance
In women, the levator muscles or their supplying nerves can be damaged in pregnancy or childbirth. This occurs more commonly after a normal vaginal delivery, but can also occur following a c-section. There is some evidence that these muscles may also be damaged during a hysterectomy. Pelvic floor exercises, also known as Kegel exercises, may improve the tone and function of the pelvic floor muscles, which is of particular benefit for women (and less commonly men) who suffer from urinary incontinence. In addition to preventing or diminishing leakage it may improve vaginal laxity, and consequent diminished sexual sensation.

Damage to the pelvic floor not only contributes to urinary incontinence but can lead to pelvic organ prolapse. Pelvic organ prolapse occurs women when pelvic organs (e.g. the vagina, bladder, rectum, or uterus) protrude into or outside of the vagina. The causes of pelvic organ prolapse are not unlike those that also contribute to urinary incontinence. These include inappropriate (asymmetrical, excessive, insufficient) muscle tone and asymmetries caused by trauma to the pelvis. Age, childbirth, family history, and hormonal status all contribute to the development of pelvic organ prolapse. The vagina is suspended by attachments to the perineum, pelvic side wall and sacrum via attachments that include collagen, elastin, and smooth muscle. Repair of lost vaginal support may involve surgery.