Corpus: Iliococcygeus muscle

The iliococcygeus muscle is the lateral part of the levator ani muscle, which belongs to the pelvic diaphragm.

The pelvic diaphragm is the inner muscle layer consisting of the levator ani muscle (comprising the puborectalis muscle, pubococcygeus muscle, and iliococcygeus muscle) and, depending on the author, the coccygeus muscle. It connects to the levator ani muscle at the back and is fused with the sacrospinous ligament.

The iliococcygeus muscle is generally a thin muscle that may be completely absent or largely replaced by connective tissue.

The iliococcygeus muscle originates from the inside of the ischial bone and from the tendinous arch of the levator ani muscle, which is the tendinous arch of the fascia of the internal obturator muscle.

The iliococcygeus muscle attaches its fibers to the coccygeal ligament in the immediate vicinity of the coccyx.

The iliococcygeus muscle is innervated by the pudendal nerve of the sacral plexus (S2-S4).

As part of the levator ani muscle, the iliococcygeus muscle serves to close the lower pelvis and lift and close the anus. Lifting the anus is an important supportive reaction during defecation. The iliococcygeus muscle is involved in stabilizing the flexura perinealis, which is part of the rectum, through its muscle tone. It plays a crucial role in maintaining fecal continence.