The superficial transverse perineal muscle is a thin, paired striated muscle running transversely across the anterior perineum from the ischial tuberosity to the perineal body. It lies superficial to the perineal membrane in the superficial perineal space, alongside the ischiocavernosus and bulbospongiosus muscles. It anchors the central perineal point, preventing anterior displacement of the perineal body during pelvic floor loading.
| Origin | Ischial tuberosity and inner surface of the ischiopubic ramus |
|---|---|
| Insertion | Perineal body (central tendon of the perineum) |
| Nerve Supply | Pudendal nerve (perineal branch, S2-S4) |
| Blood Supply | Internal pudendal artery (perineal branch) |
| Actions | Fixes and stabilises the perineal body during defaecation, urination, and sexual function |
|---|
The superficial transverse perineal muscle is torn in obstetric perineal lacerations extending beyond the posterior fourchette. In third and fourth degree tears, the perineal body is disrupted, disinsertions this muscle along with the bulbospongiosus and external anal sphincter. Reconstruction of the perineal body during episiotomy repair and obstetric laceration repair includes re-approximating the torn ends of the superficial transverse perineal muscles to restore the structural midpoint of the perineum. The perineal body it supports is palpable between the anal verge and the posterior vaginal fourchette.
Palpated as a thin transverse band on either side of the perineum, running from the ischial tuberosity toward the midline central perineal point.
Second degree perineal tears disrupt the bulbospongiosus and superficial transverse perineal muscles; third and fourth degree tears additionally involve the external and internal anal sphincters; careful layer-by-layer repair restoring the muscle anatomy and perineal body prevents chronic perineal deficiency and prolapse.
