Perineal Fascia

The perineal fascia is a layered connective tissue structure in the perineum that envelopes and separates various muscular and subcutaneous structures. It plays a crucial role in organizing the superficial and deep perineal compartments and supporting the perineal muscles, vessels, and erectile tissues. The fascia is divided into superficial and deep layers, each with distinct anatomical and functional properties.

Structure

The perineal fascia is divided into two main layers: the superficial perineal fascia and the deep perineal fascia. Each layer has subcomponents with specific attachments and relationships to surrounding structures.

1. Superficial Perineal Fascia

• Fatty layer (Camper’s fascia): Continuation of superficial abdominal fatty layer; more prominent in females, forming the labia majora and mons pubis
• Membranous layer (Colles’ fascia): Continuation of Scarpa’s fascia from the abdominal wall; forms a distinct, fibrous sheet in the urogenital triangle

2. Deep Perineal Fascia (Gallaudet’s fascia)

• Invests the superficial perineal muscles (ischiocavernosus, bulbospongiosus, superficial transverse perineal muscle)
• Continuous with the deep fascia of the external oblique and deep fascia of the penis (Buck's fascia)

Other Related Fasciae

• Perineal membrane: Though not technically part of the perineal fascia, it is a fibrous sheet that separates the superficial and deep perineal pouches
• Pelvic fascia: Lies superior to the perineum, covering pelvic organs and connecting to perineal structures

Location

The perineal fascia is located in the perineum, within the boundaries of the urogenital and anal triangles. The superficial fascia lies between the skin and the perineal membrane, while the deep fascia directly surrounds the superficial perineal muscles and erectile tissues.

Function

• Compartmentalization: Separates superficial and deep perineal spaces
• Structural Support: Provides a framework for attachment and orientation of perineal muscles
• Barrier Function: Prevents the spread of fluid or infection between fascial layers
• Erectile Tissue Support: Deep fascia supports penile and clitoral erectile tissues during arousal

Clinical Significance

• Urethral injury: Rupture of the spongy urethra can lead to urine extravasation into the superficial perineal space, bounded by Colles’ fascia
• Fascial continuity: Infections or hematomas can track from the anterior abdominal wall into the perineum through continuous fascial layers
• Surgical dissection: Precise identification of fascial layers is critical in procedures involving the perineum or genital reconstruction