Muscle · Pelvis

Coccygeus

Musculus coccygeus

The back part of the muscular floor of the pelvis, lying behind levator ani and completing the sheet that closes the pelvic outlet. It is a flat triangle running from the bony spine on the inner wall of the pelvis to the side of the coccyx and the lowest part of the sacrum. Its most useful feature is that it is inseparable from the sacrospinous ligament — the muscle lies on the ligament's pelvic surface and the two are, developmentally and structurally, one sheet in two states. It supports the pelvic organs from below and steadies the coccyx against the pressure that pushes it backward.