The levator ani is the primary muscular floor of the pelvis, a broad muscular diaphragm forming a gutter-shaped sheet from the pubis to the coccyx. It has three components — puborectalis (strongest, discussed separately), pubococcygeus, and iliococcygeus — each contributing to pelvic floor support. Weakness or avulsion of the levator ani from childbirth is the primary cause of pelvic organ prolapse and stress urinary incontinence in women.
| Origin | Tendinous arch of the levator ani (a thickening of the obturator internus fascia from the pubic body to the ischial spine), plus the pubic body (pubococcygeus and puborectalis) and ischial spine (iliococcygeus) |
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| Insertion | Perineal body, anorectal junction (puborectalis), coccyx (pubococcygeus and iliococcygeus), anococcygeal raphe |
| Nerve Supply | Nerve to levator ani from S3 and S4 (direct branches), and pudendal nerve branches |
| Blood Supply | Internal pudendal and inferior gluteal arteries |
| Actions | Supports the pelvic viscera against intra-abdominal pressure increases; Maintains urinary and faecal continence; Assists in parturition by guiding the fetal head through the pelvis; Compresses the vagina (pubovaginalis component) |
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During coughing, sneezing, or heavy lifting, intra-abdominal pressure rises dramatically. A normally functioning levator ani reflexly contracts before this pressure rise to maintain continence — the feedforward protective contraction that is specifically impaired in stress urinary incontinence and levator ani injury.
Levator avulsion injury from vaginal delivery occurs in approximately 13 to 36 percent of vaginal deliveries and is detected on perineal ultrasound or MRI as loss of the normal pubic insertion. Avulsion is most associated with prolonged second stage, forceps delivery, and large babies. Pelvic floor physiotherapy and biofeedback improve levator ani function in weakness without avulsion. Levator ani syndrome produces chronic pelvic pain and anorectal pressure from levator ani spasm.
The levator ani is assessed by digital vaginal or rectal examination, feeling the muscular floor bilaterally and assessing the squeeze contraction and bearing-down relaxation. Levator avulsion is detected as a defect in the normal muscle bulk at the pubic insertion.
Pubic insertion avulsion from vaginal delivery producing widened levator hiatus, pelvic floor dysfunction, and predisposition to pelvic organ prolapse.
Chronic levator spasm producing anorectal pressure, pelvic pain, and sitting discomfort managed with levator massage, biofeedback, and electrogalvanic stimulation.
