Perineal Membrane

The perineal membrane is a strong, fibrous sheet that spans the urogenital triangle and separates the superficial and deep perineal pouches. It provides foundational support for perineal structures and acts as a platform for attachment of muscles and erectile tissues. The membrane plays a key role in the structural integrity of the pelvic floor and contributes to urinary continence and sexual function.

Structure

The perineal membrane is a triangular, dense connective tissue layer that stretches horizontally across the anterior perineum. It contains multiple perforations to allow passage of neurovascular structures and the urethra (and vagina in females). It serves as the floor of the deep perineal pouch and the roof of the superficial perineal pouch.

Attachments

• Lateral: Ischiopubic rami
• Posterior border: Perineal body and fuses with Colles’ fascia
• Anterior border: Free edge forming the transverse perineal ligament (deep dorsal vein of the penis or clitoris passes through here)

Perforations

• Urethra (both sexes)
• Vagina (in females)
• Arteries and nerves to erectile tissues and glands

Location

The perineal membrane lies in the urogenital triangle, deep to the superficial perineal pouch and superficial to the pelvic diaphragm (levator ani). It divides the perineum into superficial and deep compartments and is a key component of the deep perineal space.

Function

• Structural support: Provides a firm base for perineal muscles and external genitalia
• Passage of structures: Allows passage of urethra, vagina (in females), and neurovascular bundles
• Compartmentalization: Forms the roof of the superficial perineal pouch and floor of the deep perineal pouch
• Muscle attachment: Anchor for superficial and deep perineal muscles

Clinical Significance

• Perineal trauma: May be torn during childbirth, especially with deep perineal lacerations
• Urinary incontinence: Weakness or disruption can affect urethral support, especially in females
• Surgical reference: Key layer in perineal and pelvic floor surgeries for reconstruction and repair