The pelvic floor Flashcards
what is the pelvic visera
The pelvic viscera (bladder, rectum, pelvic genital organs and terminal part of the urethra) reside within the pelvic cavity (or the true pelvis).
where is the pelvic cavity located
This cavity is located within the lesser part of the pelvis, beneath the pelvic brim.
whoch muscles help make up the wal.l of the cavity
A number of muscles help make up the walls of the cavity – the lateral walls include the obturator internus and the pirformis muscle, with the latter also forming the posterior wall
what is another name for pelvic floor
pelvic diaphragm
strucutre of the pelvic floor
The pelvic floor is a funnel-shaped structure. It attaches to the walls of the lesser pelvis, separating the pelvic cavity from the perineum inferiorly (region which includes the genitalia and anus).
In order to allow for urination and defecation, there are a few gaps in the pelvic floor. There are two ‘holes’ that have significance:
Urogenital hiatus – an anteriorly situated gap, which allows passage of the urethra (and the vagina in females).
Rectal hiatus – a centrally positioned gap, which allows passage of the anal canal.
Between the urogenital hiatus and the anal canal lies a fibrous node known as the perineal body, which joins the pelvic floor to the perineum (described further here).
functions of the pelvic floor
As the floor of the pelvic cavity, these muscles have important roles to play in the correct functioning of the pelvic and abdominal viscera.
The roles of the pelvic floor muscles are:
Support of abdominopelvic viscera (bladder, intestines, uterus etc.) through their tonic contraction.
Resistance to increases in intra-pelvic/abdominal pressure during activities such as coughing or lifting heavy objects.
Urinary and fecal continence.The muscle fibers have a sphincter action on the rectum and urethra. They relax to allow urination and defecation.
muscles of the pelvic floor
When learning about the muscles of the pelvic floor, it is important to keep in mind its funnel-shaped structure. There are three main components of the pelvic floor:
Levator ani muscles (largest component).
Coccygeus muscle.
Fascia coverings of the muscles.
We shall now consider each of these components in more detail.
desribe the levator ani muscles
The levator ani is a broad sheet of muscle. It is composed of three separate paired muscles; pubococcygeus, puborectalis and iliococcygeus.
These muscles have attachments to the pelvis as follows:
Anterior – pubic bodies of the hip bone.
Laterally – thickened fascia of the obturator internus muscle, known as the tendinous arch.
Posteriorly – ischial spines of the hip bone.
desirbe the puborectalis
The puborectalis muscle is a U-shaped sling, extending from the bodies of the pubic bones, past the urogenital hiatus, around the anal canal. Its tonic contraction bends the canal anteriorly, creating the anorectal angle (90 degrees) at the anorectal junction (where the rectum meets the anus).
The main function of this thick muscle is to maintain faecal continence – during defecation this muscle relaxes.
Some fibers of the puborectalis muscle (pre-rectal fibers) form another U-shaped sling that flank the urethra in the male and the urethra and vagina in the female (in some textbooks they appear as pubovaginalis or sphincter urethrae / vaginae). These fibers are very important in preserving urinary continence, especially during abrupt increase of the intra-abdominal pressure i.e. during sneezing.
desrubie Pubococcygeus
The muscle fibres of the pubococcygeus are the main constituent of the levator ani. They arise from the body of the pubic bone and the anterior aspect of the tendinous arch. The fibres travel around the margin of the urogenital hiatus and run posteriomedially,attaching at the coccyx and anococcygeal ligament.
Iliococcygeus
what are the cooccygeus muscles
The coccygeus (or ischiococcygeus) is the smaller, and most posterior pelvic floor component – as the levator ani muscles are situated anteriorly.
It originates from the ischial spines and travels to the lateral aspect of the sacrum and coccyx, along the sacrospinous ligament.
