The iliococcygeus is a muscle of the pelvic floor. It forms the posterolateral part of the levator ani muscle group.
- Attachments: 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. It also blends with the fibres of the contralateral muscle in the midline of the pelvic floor.
- Actions: Elevates the pelvic floor and anorectal canal.
- Innervation: Nerve to levator ani and branches of the pudendal nerve.
- Blood supply: Inferior gluteal, inferior vesical and pudendal arteries.
Adapted from work by OpenStax [CC BY 4.0], via Wikimedia Commons
Fig 1 – Superior (bird’s eye) view of the pelvic floor. Note the prerectal fibres of the puborectalis.