The levator ani is a thin, wide muscle, located on either side of the pelvis. It is made up of three muscular components: puborectalis, pubococcygeus (which includes puborectalis, therefore, together called the puborectal muscle-pubococcygeus complex) and iliococcygeus muscle.
It is attached to the inner surface of each side of the lower pelvis, and it is united to form a larger part of the pelvic floor. The coccygeus muscle complements the pelvic floor also called the pelvic diaphragm .
It supports the viscera in the pelvic cavity, and surrounds the various structures that pass through it.
The levator ani is the primary pelvic floor muscle and painfully contracts during vaginismus. It also contracts rhythmically during orgasm.
Video Levator ani
Structure
The anne levator consists of three parts:
- Muscle Iliococcygeus
- pubococcygeus muscles
- Pubopathic muscles
Iliococcygeus arises from the inner side of the ischium (the lower and back of the hip bone) and from the posterior part of the tendon fascia obturator, and attached to the tail bone and the anococcygeal body; usually thin, and may be absent, or mostly replaced by fibrous tissue. The accessory slip on the back is sometimes called iliosacralis .
Pubococcygeus muscle has medial fibers that make pubovaginalis in females, and puboprostaticus in males.
Origin and insertion
The levator ani appears, in the front, of the posterior surface of the maxillary lateral symphysis pubic ramus; on the back, of the inner surface of the iscium spine; and between these two points, of the obturator fascia.
Posterior, the origin of the fascia is appropriate, more or less closely, with the pelvic fascia tendon arch, but in the front, the muscle emerges from the fascia at varying distances over the arch, in some cases reaching almost as high as the channel for the obturator and nerve vessels.
The fibers pass down and back to the midline of the pelvic floor; the most posterior is inserted into the side of the last two segments of the coccyx; those placed more anteriorly together with muscles from the opposite side, in the median fibrous ridge called the anococcygeal or raphe body, which extends between the coccyx and the anus margin.
The middle fiber is inserted into the side of the rectum, blending with the sphincter muscle fibers; lastly in men, the anterior fibers descend to the prostate side to fuse underneath with the muscles from opposite sides, joining the external anal sphincter fibers and transverse perineal muscles, at the point of the central tendine of the perineum.
The anterior portion is sometimes separated from the rest of the muscle by connective tissue.
From this state, as well as from its strange relationship with the prostate, which it supports as in the sling, has been described as a different muscle, with the name of levator prostatÃÆ'Â| .
In women, anterior fibers of levator ani come down to the side of the vagina.
Innervation
The levator ani muscle is mostly innervated by the pudendal nerve, the perineal nerve and the inferior rectal nerves that work together.
Variations
In addition, the sacral spinal cord (S3, S4) also directs the muscles directly (in ~ 70% of people). Sometimes (in ~ 40% of people) the inferior rectal nerve innervates the levator ani muscles independently of the pudendal nerve.
Maps Levator ani
Pubococcygeus
The pubococcygeus muscle or PC muscle is a hollow-like muscle, found in both sexes, extending from the pubic bone to the coccyx to form the floor of the pelvic cavity and supports pelvic organs.
Structure
Pubococcygeus emerges from the back of the pubis and from the anterior part of the obturator fascia, and is directed back almost horizontally along the side of the anal canal to the coccyx and sacrum, which finds its attachment.
Between the cessation of the vertebral and anal columns, the two pubococcygeus muscles converge and form a thick fibromuscular layer located on the raphe (ridge) or (anococcygeal body) formed by iliococcygei.
The largest part of this muscle is inserted into the coccyx and into the last one or two sections of the sacrum.
Variations
This insertion into the vertebral column, however, is not accepted by all observers.
Function
Pubococcygeus muscle controls the flow of urine and contracts during orgasm and helps in male ejaculation. It also helps in labor as well as core stability.
Strong pubococcygeus muscle has also been associated with decreased urinary incontinence and proper positioning of the baby's head during labor.
Kegel exercises
Kegel exercises are a series of voluntary contractions of all the perineal muscles. The movement is performed in an effort to strengthen all striated muscles in the perineal region. They are often referred to simply as "kegels", named after their founder, Dr. Arnold Kegel. These exercises also serve to contract, among other things, the muscles of ischiocavernosus, bulbospongiosus, and cremaster in men, because the voluntary contraction of pubococcygeus muscle also involves a cremasteric reflex, which lifts the testicles upward, although this does not occur in all men. Kegel exercises have been prescribed to correct erectile dysfunction due to venous leakage and to help men control premature ejaculation and to treat urinary incontinence in both sexes.
Puborectalis
The fibers that form the sling for the rectum are named puborectalis . They arise from the lower part of the symphysis pubis, and from the superior fascia of the urogenital diaphragm.
They meet with fibers corresponding to the opposite side around the bottom of the rectum, and form it as a strong arms. Relaxation increases the angle between the rectum and the anus, allowing bowel movements along with internal and external anal sphincter relaxation.
Function
The levator ani muscle is responsible for "shaking" the tail in four-legged animals. These muscles are not as strong as humans, because the tail is more demanding than the supporting function that the muscles serve in humans.
Clinical definitions
Levator ani Syndrome
Sindrom Levator ani adalah nyeri dubur episodik yang disebabkan oleh spasme otot levator ani.
Gambar tambahan
Lihat juga
- Otot Bulbospongiosus
- Coccygectomy
Referensi
This article combines text in the public domain of page 422 of the 20th edition of Gray's Anatomy (1918)
External links
- Anatomical figure: 41: 05-00 in Human Anatomy Online, SUNY Downstate Medical Center - "Female superficial perineal pocket muscle."
- Anatomical figure: 42: 04-00 in Human Anatomy Online, SUNY Downstate Medical Center - "Male superficial perineal pocket muscle."
- Photo anatomy: 43: 16-0102 at SUNY Downstate Medical Center - "Pelvic Diaphragm Muscles"
- Anatomical image: 9072 in Suny Downstate Medical Center
- Anatomical image: 9089 in SUNY Downstate Medical Center
- Anatomical image: 9871 in Suny Downstate Health Center
- Cross-section image: pelvis-e12-15 - Plastination Laboratory at Vienna Medical University
- perineum at The Anatomy Lesson by Wesley Norman (Georgetown University) ( analtriangle3 ) * pelvis at The Anatomy Lesson by Wesley Norman (Georgetown University) ( femalepelvicdiaphragm , > malepelvicdiaphragm )
- Merck's Guide article on levator ani syndrome
Source of the article : Wikipedia
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