Anatomy in detail.
The pelvic floor consists of several muscles within a web of connective tissues, attaching to the bones of the pelvis, sacrum and coccyx.
The anatomy of the pelvic floor (sometimes called the pelvic diaphragm) is complex and the terminology used varies between sources.
Take these lines from an academic paper:
The pelvic floor is comprised of a number of muscles ...
(No actual number given...)
... organized into superficial and deep muscle layers ...
(Described as 2 or 3 layers, depending on the source material.)
There is significant controversy with regards to the nomenclature ...
(Lots of complicated names that people can't agree on!)
For practical purposes, the exact details are not important but see below for details of individual muscles.
What is important is learning to use your pelvic floor muscles. Being able to activate them and feel them as the base foundation for all movement.
Keep looking at the images. Picture your anatomy in your mind to increase your awareness of your body. Build the connection.
The pelvic floor consists of the levator ani muscle group and the coccygeus.
All are thin muscles that together span the pelvic canal at the base of the torso.
The coccygeus muscles (a.k.a. ischiococcygeus) form the posterior (back) part of the pelvic floor.
Coccygeus ~ near the coccyx.
Paired muscles that are triangular in shape.
Made up of muscular and connective tissue fibres.
The coccygeus muscles attach to:
The levator ani muscles form the anterior (front) part of the pelvic floor.
The levator ani consists of three muscles on each side (left and right):
The iliococcygeus muscles are the lateral parts of the levator ani.
Ilioccocygeus ~ ilio (covering term for ilium and ischium bones of pelvis) to coccyx.
Thin and triangular-shaped, consisting of muscle and fibrous tissue.
The iliococcygeus is the actual “levator” muscle of the levator ani muscle group, elevating the pelvic floor and the anorectal canal.
The iliococcygeus muscles attach to:
The iliococygeus may fail entirely, or be largely replaced by fibrous tissue.(need ref.)
An accessory slip at the posterior part of the iliococcygeus is sometimes named the iliosacralis.
The most medial (near midline) muscles of the levator ani group, like a hammock from front to back of the pelvic floor.
Pubococcygeus ~ pubis (pubic bone of pelvis) to coccyx.
The pubococcygeus muscles attach to:
Puborectalis ~ pubis (pubic bone of pelvis) + rectum.
The puborectalis muscles are relatively thick muscles, forming a U-shaped sling past the urogenital hiatus and around the anus.
These muscles maintain faecal continence and relax during defecation.
The puborectalis muscles attach to:
The puborectalis muscles encircles the rectum (anorectal junction) some fibres are interwoven with the external anal sphincter.
Some fibres of the puborectalis muscles (pre-rectal fibres) form another U-shaped sling that flank the urethra (and vagina in the female) pubovaginalis or sphincter urethrae / vaginae). These fibres are very important in preserving urinary continence.
The pubococcygeus and puborectalis muscles have intervening and inseparable muscle fibres as they originate on the pubis.
The puborectalis muscle is located in between the superficial and deep muscle layers and some sources classify it as the middle muscle layer of the pelvic floor.
The anococcygeal body (a.k.a. anococcygeal ligament a.k.a anococcygeal raphe) is a midline musculo-tendinous structure between the coccyx and the anus.
It consists of three layers:
The inner border of the pubococcygeus muscles forms the margin of the levator (urogenital) hiatus, the hole through which passes the urethra, anorectum and in females the vagina.The levator plate is formed by an overlap of the puborectalis, iliococcygeus, and pubococcygeus muscle fibres
The pelvic floor (pelvic diaphragm) muscles lie deep (more internal) to the superfical perineal muscle layer of the pelvis.
The urogenital diaphragm (a.k.a. perineal membrane) is a musculofascial structure present over the anterior pelvic outlet that closes the urogenital (levator) hiatus. The structure of the urogential diaphragm is subject to discussion/controversy.
The ischiocavernosus and bulbocavernosus muscles, and thin slips of the superficial transverse perinei, complete the inferior aspect of the urogenital diaphragm. The structure bridges the gap between the inferior pubic rami bilaterally and the perineal body.
The external anal sphincter, perineal body and possibly the puboperineal (or transverse perinei) muscles are the muscles relevant to anal canal function.
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PELVIC FLOOR ANATOMY AND APPLIED PHYSIOLOGY Varuna Raizada, M.D. and Ravinder K. Mittal, M.D.
FEMALE PELVIC FLOOR ANATOMY Sender Herschorn, MD, FRCSC
The determinants of minimal levator hiatus and their relationship to the puborectalis muscle and the levator plate Shobeiri, G Rostaminia, D White, LH Quiroz
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