Muscle
Iliococcygeus
A thin lateral levator component contributing to the levator plate
High-yield
Iliococcygeus arises mainly from the tendinous arch, not the iliac bone. Its posterior fibers contribute to the levator plate beneath pelvic structures.
Overview
Iliococcygeus extends from the tendinous arch and ischial spine toward the posterior midline and coccyx. Much of it may be thin or aponeurotic. Together with the opposite side, it contributes to the posterior support surface often called the levator plate.
Reference facts
- Origin
- From the tendinous arch of levator ani on obturator internus fascia and the ischial spine.
- Insertion
- Into the posterior midline anococcygeal tissues and coccyx, blending with fibers from the opposite side.
- Innervation
- Direct sacral branches through the nerve to levator ani, principally S3–S4; reported additional contributions vary.
- Action
- Helps elevate and support the pelvic floor and contributes to the posterior levator plate.
- Blood supply
- Small internal iliac branches, including inferior gluteal and internal pudendal contributions.
Clinical correlation
Pelvic support depends on muscle, fascia and apical ligaments together. MRI studies associate a more downward-directed levator plate with prolapse, but normal support does not require a perfectly horizontal plate.
Frequently asked questions
What does the iliococcygeus do?
The iliococcygeus helps elevate and support the pelvic floor and contributes to the posterior levator plate.
What nerve innervates the iliococcygeus?
Direct sacral branches through the nerve to levator ani, principally S3–S4; reported additional contributions vary.
Where does the iliococcygeus attach?
Origin: From the tendinous arch of levator ani on obturator internus fascia and the ischial spine. Insertion: Into the posterior midline anococcygeal tissues and coccyx, blending with fibers from the opposite side.
What is the blood supply of the iliococcygeus?
The iliococcygeus is supplied by the small internal iliac branches, including inferior gluteal and internal pudendal contributions.