Pelvic floor
From Wikipedia, the free encyclopedia
| Pelvic floor | |
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| Left Levator ani from within. | |
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| Coronal section through the anal canal. B. Cavity of urinary bladder V.D. Ductus deferens. S.V. Seminal vesicle. R. Second part of rectum. A.C. Anal canal. L.A. Levator ani. I.S. Sphincter ani internus. E.S. Sphinear ani externus. | |
| Latin | diaphragma pelvis |
| Gray's | subject #119 420 |
| Nerve | Sacral nerves 3-4 [1] |
| Dorlands/Elsevier | d_15/12293527 |
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 diaphragm is a muscular partition formed by the levatores ani and coccygei, with which may be included the parietal pelvic fascia on their upper and lower aspects. The pelvic floor separates the pelvic cavity above from the perineal region (including perineum) below.
The right and left levator ani lie almost horizontally in the floor of the pelvis, separated by a narrow gap that transmits the urethra, vagina, and anal canal. The levator ani is usually considered in three parts: pubococcygeus, puborectalis, and iliococcygeus. The pubococcygeus, the main part of the levator, runs backward from the body of the pubis toward the coccyx and may be damaged during parturition. Some fibers are inserted into the prostate, urethra, and vagina. The right and left puborectalis unite behind the anorectal junction to form a muscular sling . Some regard them as a part of the sphincter ani externus. The iliococcygeus, the most posterior part of the levator ani, is often poorly developed.
The coccygeus, situated behind the levator ani and frequently tendinous as much as muscular, extends from the ischial spine to the lateral margin of the sacrum and coccyx.
The pelvic cavity of the true pelvis has the pelvic floor as its inferior border (and the pelvic brim as its superior border.) The perineum has the pelvic floor as its superior border.
Some sources do not consider "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.[2] However, other sources include the fascia as part of the diaphragm. [3] In practice, the two terms are often used interchangeably.
Inferiorly, the pelvic floor extends into the anal triangle.
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[edit] 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.
[edit] 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 experience urinary incontinence. In addition to preventing or diminishing leakage it may improve vaginal muscle tone and consequent sexual sensation.
Damage to the pelvic floor not only contributes to urinary incontinence but can lead to pelvic organ prolapse. Pelvic organ prolapse occurs in 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.
Perineology or Pelviperineology is a speciality dealing with the functional troubles of the three axis (urological, gynaecological and coloproctological) of the pelvic floor. "A unitary view of the pelvic organs function then creates a sort of superspecialty that must open new spaces to the research insuring to the patients more rational solutions. Perineology is then a medical branch of which we probably will hear talking more and more in the future." ([G. Dodi, RICP 1990; 9: 113][1])
[edit] See also
[edit] Additional images
 Coronal section of pelvis, showing arrangement of fasciæ. Viewed from behind. |
 The arteries of the pelvis. |
 Iliac colon, sigmoid or pelvic colon, and rectum seen from the front, after removal of pubic bones and bladder. |
 Male pelvic organs seen from right side. |
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[edit] References
- ^ Human anatomy at Dartmouth part_6/chapter_37.html#chpt_37_innervation_diaphragm
- ^ (2005) Gray's Anatomy For Students, 391.
- ^ Pelvic+diaphragm at eMedicine Dictionary
[edit] External links
- Overview at nih.gov
- Selection of recent medical literature continuously updated on Pelvic Floor Functional Anatomy
- Pelviperineology The Open Access Journal who consider all the compartments of the pelvis and of the perineum, with the body around and the mind above, as a single unit.
This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
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