Pelvic floor
   HOME

TheInfoList



OR:

The pelvic floor or pelvic diaphragm is composed of muscle fibers of the
levator ani The levator ani is a broad, thin muscle group, situated on either side of the pelvis. It is formed from three muscle components: the pubococcygeus, the iliococcygeus, and the puborectalis. It is attached to the inner surface of each side of the ...
, the coccygeus muscle, and associated
connective tissue Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...
which span the area underneath the
pelvis The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...
. 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 The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains the reproduc ...
above from the perineal region (including
perineum The perineum in humans is the space between the anus and scrotum in the male, or between the anus and the vulva in the female. The perineum is the region of the body between the pubic symphysis (pubic arch) and the coccyx (tail bone), includi ...
) below. Both males and females have a pelvic floor. To accommodate the birth canal, a female's pelvic cavity is larger than a male's.


Structure

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 The levator ani is a broad, thin muscle group, situated on either side of the pelvis. It is formed from three muscle components: the pubococcygeus, the iliococcygeus, and the puborectalis. It is attached to the inner surface of each side of the ...
, 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
birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the f ...
. 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
external anal sphincter The external anal sphincter (or sphincter ani externus ) is a flat plane of skeletal muscle fibers, elliptical in shape and intimately adherent to the skin surrounding the margin of the anus. Anatomy The external anal sphincter measures about 8 ...
. 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 The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains the reproduc ...
of the
true pelvis The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains the reprodu ...
has the pelvic floor as its inferior border (and the pelvic brim as its superior border). The
perineum The perineum in humans is the space between the anus and scrotum in the male, or between the anus and the vulva in the female. The perineum is the region of the body between the pubic symphysis (pubic arch) and the coccyx (tail bone), includi ...
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. However, other sources include the
fascia A fascia (; plural fasciae or fascias; adjective fascial; from Latin: "band") is a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches to, stabilizes, encloses, and separates muscles and other internal organs ...
as part of the diaphragm. In practice, the two terms are often used interchangeably. Posteriorly, the pelvic floor extends into the
anal triangle The anal triangle is the posterior part of the perineum. It contains the anal canal. Structure The anal triangle can be defined either by its vertices or its sides. * ''Vertices'' ** one vertex at the coccyx bone ** the two ischial tuberosities ...
. The pelvic floor has two hiatuses (gaps): Anteriorly urogenital hiatus through which
urethra The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra ...
and
vagina In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen ...
pass through and posteriorly rectal hiatus through which
anal canal The anal canal is the part that connects the rectum to the anus, located below the level of the pelvic diaphragm. It is located within the anal triangle of the perineum, between the right and left ischioanal fossa. As the final functional segme ...
passes.


Function

It is important in providing support for pelvic
viscera In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a f ...
(organs), e.g. the
bladder The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine en ...
,
intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans an ...
s, the
uterus The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...
(in females), and in maintenance of continence as part of the urinary and
anal Anal may refer to: Related to the anus *Related to the anus of animals: ** Anal fin, in fish anatomy ** Anal vein, in insect anatomy ** Anal scale, in reptile anatomy *Related to the human anus: ** Anal sex, a type of sexual activity involving s ...
sphincters. It facilitates birth by resisting the descent of the presenting part, causing the fetus to rotate forwards to navigate through the pelvic girdle. It helps maintain optimal intra-abdominal pressure.


Clinical significance

The pelvic floor is subject to clinically relevant changes that can result in: * Anterior vaginal wall prolapse **
Cystocele A cystocele, also known as a prolapsed bladder, is a medical condition in which a woman's bladder bulges into her vagina. Some may have no symptoms. Others may have trouble starting urination, urinary incontinence, or frequent urination. Complicat ...
(bladder into vagina) **
Urethrocele A urethrocele is the prolapse of the female urethra into the vagina. Weakening of the tissues that hold the urethra in place may cause it to protrude into the vagina. Urethroceles often occur with cystoceles (involving the urinary bladder as well ...
(urethra into vagina) ** Cystourethrocele (both bladder and urethra) * Posterior vaginal wall prolapse **
Enterocele An enterocele is a protrusion of the small intestines and peritoneum into the vaginal canal. It may be treated transvaginally or by laparoscopy. An enterocele may also obstruct the rectum, leading to symptoms of obstructed defecation. Enteroceles ...
(small intestine into vagina) **
Rectocele In gynecology, a rectocele ( ) or posterior vaginal wall prolapse results when the rectum bulges ( herniates) into the vagina. Two common causes of this defect are childbirth and hysterectomy. Rectocele also tends to occur with other forms of pe ...
(rectum into vagina) * Apical vaginal prolapse **
Uterine prolapse Uterine prolapse is when the uterus descends towards or through the opening of the vagina. Symptoms may include vaginal fullness, pain with sex, trouble urinating, urinary incontinence, and constipation. Often it gets worse over time. Low back ...
(uterus into vagina) **
Vaginal vault The vaginal vault is the expanded region of the vaginal canal at the internal end of the vagina. Prolapse The vaginal vault may prolapse after a hysterectomy, as there is no uterus supporting the interior end of the vagina. ''Colposacropexy'' ...
prolapse (roof of vagina) - after
hysterectomy Hysterectomy is the surgical removal of the uterus. It may also involve removal of the cervix, ovaries ( oophorectomy), Fallopian tubes ( salpingectomy), and other surrounding structures. Usually performed by a gynecologist, a hysterectomy may b ...
Pelvic floor dysfunction can result after treatment for gynecological cancers. Damage to the pelvic floor not only contributes to urinary incontinence but can lead to pelvic organ
prolapse In medicine, prolapse is a condition in which organs fall down or slip out of place. It is used for organs protruding through the vagina, rectum, or for the misalignment of the valves of the heart. A spinal disc herniation is also sometimes ca ...
. 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, pregnancy, 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. Surgery can be performed to repair pelvic floor muscles. The pelvic floor muscles can be strengthened with
Kegel exercise Kegel exercise, also known as pelvic-floor exercise, involves repeatedly contracting and relaxing the muscles that form part of the pelvic floor, now sometimes colloquially referred to as the "Kegel muscles". The exercise can be performed many t ...
s. Disorders of the posterior pelvic floor include rectal prolapse,
rectocele In gynecology, a rectocele ( ) or posterior vaginal wall prolapse results when the rectum bulges ( herniates) into the vagina. Two common causes of this defect are childbirth and hysterectomy. Rectocele also tends to occur with other forms of pe ...
, perineal hernia, and a number of functional disorders including anismus.
Constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel moveme ...
due to any of these disorders is called "functional constipation" and is identifiable by clinical diagnostic criteria. Pelvic floor exercise (PFE), also known as
Kegel exercises Kegel exercise, also known as pelvic-floor exercise, involves repeatedly contracting and relaxing the muscles that form part of the pelvic floor, now sometimes colloquially referred to as the "Kegel muscles". The exercise can be performed many ti ...
, may improve the tone and function of the pelvic floor muscles, which is of particular benefit for women (and less commonly men) who experience
stress urinary incontinence Stress incontinence, also known as stress urinary incontinence (SUI) or effort incontinence is a form of urinary incontinence. It is due to inadequate closure of the bladder outlet by the urethral sphincter. Pathophysiology It is the loss of sma ...
. However, compliance with PFE programs often is poor, PFE generally is ineffective for urinary incontinence unless performed with
biofeedback Biofeedback is the process of gaining greater awareness of many physiological functions of one's own body by using electronic or other instruments, and with a goal of being able to manipulate the body's systems at will. Humans conduct biofeed ...
and trained supervision, and in severe cases it may have no benefit. Pelvic floor muscle tone may be estimated using a perineometer, which measures the pressure within the vagina. Medication may also be used to improve continence. In severe cases, surgery may be used to repair or even to reconstruct the pelvic floor. Perineology or pelviperineology is a speciality dealing with the functional troubles of the three axes (urological, gynaecological and coloproctological) of the pelvic floor.


Additional images

Gray404.png, The pelvic floor muscles span the bottom of the pelvis. This image shows the left
levator ani The levator ani is a broad, thin muscle group, situated on either side of the pelvis. It is formed from three muscle components: the pubococcygeus, the iliococcygeus, and the puborectalis. It is attached to the inner surface of each side of the ...
from within. Gray241.png Gray242.png


See also

*
Coccyx The coccyx ( : coccyges or coccyxes), commonly referred to as the tailbone, is the final segment of the vertebral column in all apes, and analogous structures in certain other mammals such as horses. In tailless primates (e.g. humans and othe ...
(tailbone) *
Female genital prolapse Pelvic organ prolapse (POP) is characterized by descent of pelvic organs from their normal positions. In women, the condition usually occurs when the pelvic floor collapses after gynecological cancer treatment, childbirth or heavy lifting. In m ...
*
Pelvic floor dysfunction Pelvic floor dysfunction is a term used for a variety of disorders that occur when pelvic floor muscles and ligaments are impaired. The condition affects up to 50 percent of women who have given birth. Although this condition predominantly affect ...
* Perineology * Perineal hernia *
Pubococcygeus muscle The levator ani is a broad, thin muscle group, situated on either side of the pelvis. It is formed from three muscle components: the pubococcygeus, the iliococcygeus, and the puborectalis. It is attached to the inner surface of each side of t ...
*
Vaginal support structures The vaginal support structures are those muscles, bones, ligaments, tendons, membranes and fascia, of the pelvic floor that maintain the position of the vagina within the pelvic cavity and allow the normal functioning of the vagina and other re ...
*
Vesicovaginal fistula Vesicovaginal fistula (VVF) is a subtype of female urogenital fistula (UGF). Presentation Vesicovaginal fistula, or VVF, is an abnormal fistulous tract extending between the bladder ('' vesica'') and the vagina that allows the continuous involu ...


References


External links


Overview at nih.gov
{{Authority control Sexual anatomy Muscles of the torso Women's health