Superficial Transverse Perineal Muscle

The superficial transverse perineal muscle is a slender, bilateral muscle found in the superficial perineal pouch of the urogenital triangle. It plays a key role in stabilizing the central point of the perineum, known as the perineal body, and contributes to the structural support of pelvic organs. Though small and often overlooked, it is essential for maintaining the integrity of the perineal region, particularly during increased intra-abdominal pressure or childbirth.

Structure

This muscle is flat, strap-like, and composed of skeletal muscle fibers. It runs transversely from the ischial tuberosity toward the midline perineal body. It is paired, with one muscle on each side, converging at the central tendon of the perineum.

Origin and Insertion

• Origin: Ischial tuberosity
• Insertion: Perineal body (central tendon of the perineum)

Fascial Layer

• Located within the **superficial perineal pouch**
• Covered by Gallaudet’s fascia (deep perineal fascia)

Location

The superficial transverse perineal muscle lies horizontally in the urogenital triangle. It is more posterior than the bulbospongiosus and ischiocavernosus muscles, and it helps demarcate the boundary between the superficial urogenital and anal triangles.

Function

• Stabilizes the perineal body: Provides anchorage for multiple muscles and supports pelvic floor structure
• Supports pelvic organs: Helps resist downward displacement of pelvic viscera
• Coordinates with nearby muscles: Works with bulbospongiosus and external anal sphincter for functional integrity of perineum

Innervation

• Deep branch of the perineal nerve (from pudendal nerve, S2–S4)

Blood Supply

• Perineal branches of the internal pudendal artery

Clinical Significance

• Obstetric trauma: Commonly torn during childbirth, contributing to perineal body weakening
• Pelvic organ prolapse: Weakness or injury may impair pelvic floor support mechanisms
• Perineal repair procedures: Often reconstructed during episiotomy or perineorrhaphy