Muscle
Levator ani
The muscular support surrounding the pelvic hiatus
High-yield
Puborectalis forms the anorectal sling; pubovisceral fibers attach to pelvic outlet structures; iliococcygeus contributes posterior support. Naming subdivisions does not make them functionally independent.
Overview
Levator ani forms most of the pelvic diaphragm and curves around the openings for the pelvic outlets. Its puborectal, pubococcygeal or pubovisceral, and iliococcygeal components have different attachments and mechanical roles. Their coordinated activity supports organs and contributes to continence.
Reference facts
- Origin
- From the pubis, tendinous arch on obturator internus fascia and region of the ischial spine.
- Insertion
- Fibers reach the perineal body, visceral walls, posterior midline and coccyx; puborectalis instead joins its opposite side behind the anorectal junction.
- Innervation
- Direct sacral branches through the levator ani nerve, commonly S3–S4 with variation into S5. Pudendal contributions have been found in some studies but not others.
- Action
- Supports pelvic organs, helps control the hiatus and anorectal angle, and coordinates with urethral and anal sphincters during storage and emptying.
- Blood supply
- Supplied by several internal iliac branches, including inferior gluteal, pudendal and visceral pelvic branches.
Clinical correlation
Childbirth can injure the pubic levator attachment and enlarge the hiatus, increasing the risk of prolapse. Pelvic support still depends on interacting muscles, connective tissue and ligaments; muscle injury does not make ligaments the sole remaining support.
Frequently asked questions
What does the levator ani do?
Supports pelvic organs, helps control the hiatus and anorectal angle, and coordinates with urethral and anal sphincters during storage and emptying.
What nerve innervates the levator ani?
Direct sacral branches through the levator ani nerve, commonly S3–S4 with variation into S5. Pudendal contributions have been found in some studies but not others.
Where does the levator ani attach?
Origin: From the pubis, tendinous arch on obturator internus fascia and region of the ischial spine. Insertion: Fibers reach the perineal body, visceral walls, posterior midline and coccyx; puborectalis instead joins its opposite side behind the anorectal junction.
What is the blood supply of the levator ani?
The levator ani is supplied by the supplied by several internal iliac branches, including inferior gluteal, pudendal and visceral pelvic branches.