The coccygeus (ischiococcygeus) forms the posterior part of the pelvic diaphragm, completing the pelvic floor between the ischial spine and the coccyx. It is the posterior counterpart to the levator ani.
| Origin | Ischial spine and sacrospinous ligament |
|---|---|
| Insertion | Lateral surface of the coccyx and lower sacrum |
| Nerve Supply | Nerve to coccygeus — branches of S4, S5 |
| Blood Supply | Inferior gluteal and internal pudendal arteries |
| Actions | Flexes the coccyx — draws it anteriorly after childbirth defaecation; Supports the pelvic floor posteriorly; Part of the pelvic diaphragm |
|---|
Coccygeus pain (coccydynia) from coccyx fracture or dislocation can involve the muscle insertion on the coccyx. Coccygeus is the muscle addressed in sacrospinous ligament fixation for vaginal vault prolapse — the sacrospinous ligament runs within the coccygeus muscle belly.
Not palpable externally. Assessed by anorectal examination.
The sacrospinous ligament running within the coccygeus muscle belly — the reference for sacrospinous fixation suture placement in vaginal vault prolapse repair, with careful attention to the sciatic nerve and pudendal vessels posterior to the ligament.
