Coccygeus is a muscle of pelvic floor, located posterior to the levator ani and anterior to the sacrospinous ligament. The muscle is triangular in shape and contains tendinous fibers. In combination with the levatores ani of both sides, the two muscles forms the pelvic diaphragm.
The triangular muscle arises by its apex from the spine of ischium.
The base of the triangular muscle is inserted into the margin of the coccyx and into the side of the lowest piece of the sacrum.
Coccygeus is innervated by a branch of fourth and fifth sacral nerves.
The two muscles assist the levatores ani in supporting pelvic viscera.