The pelvic floor, or pelvic diaphragm, spans the area beneath the pelvis and separates the pelvic cavity from the perineal region below, which includes the genitalia and anus. It supports abdominopelvic viscera, securing them and preventing prolapse when straining. It is also important for urinary and fecal continence. And it releases pressure in the abdomen and pelvis when you cough or lift something heavy. These muscles can be weakened due to trauma, age, straining, and obesity, resulting in pelvic floor dysfunction, which can cause incontinence, pain, genitourinary prolapse, and sexual dysfunction.
The pelvic floor is made up of the levator ani, coccygeus muscle, and their associated connective tissue - superior and inferior fascia of the pelvic floor. There are gaps in the pelvic floor to allow for urination and defecation – specifically the urogenital hiatus and the rectal hiatus. To accommodate the birth canal, the female pelvic cavity is larger than the male one. The urogenital hiatus is the anterior gap, and it allows the urethra through, as well as the vagina in people who have one. The rectal hiatus lets through the anal canal.
It is important to remember that the pelvic floor is funnel shaped. It extends from the pubic symphysis to the coccyx and from one lateral wall of the pelvis to the other.
The levator ani is made up of three paired muscles – the puborectalis, pubococcygeus, and iliococcygeus. The puborectalis is a sling-shaped muscle important for maintaining fecal continence. It originates from the pubis’ posterior surface on one side and attaches to the contralateral side. This muscle has tonic contraction – meaning that it has sustained contraction maintaining continual muscle tension. This muscle is inhibited, and so relaxes, during defecation. The sling goes around the anorectal junction, a bend in the gastrointestinal tract where the rectum transitions into the anus. When the sling is tight, it prevents evacuation of feces by maintaining this bend. When you choose to evacuate, it relaxes and the release of tension at the anorectal junction allows matter in the rectum to enter the anus. The pubococcygeus gives stability and support to abdominal and pelvic organs. It originates from the pelvis’ posterior surface. This muscle can be damaged during childbirth. The iliococcygeus elevates the pelvic floor and anorectal canal. It originates from the ischial spines and the posterior tendinous arch of the internal obturator fascia. It inserts onto the coccyx, perineal body, and anococcygeal ligament.
The coccygeus is a triangular muscle found posterior to the levator ani muscle group. It supports the pelvic viscera and flexes the coccyx.

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