Structure:

The membranous layer of abdominal subcutaneous tissue is the deep layer of the superficial fascia of the anterior abdominal wall. It lies immediately deep to the superficial fatty layer (Camper’s fascia) and superficial to the muscular aponeuroses of the abdominal wall.[1]

Laterally, it attaches to the aponeurosis of the external oblique muscle. Medially, it blends with the linea alba and attaches inferiorly to the pubic symphysis and pubic crest.[1] Inferior to the inguinal ligament, it continues into the perineum, where it becomes continuous with Colles’ fascia. In individuals assigned male at birth, it extends into the scrotum and contributes to the superficial fascial layers associated with the spermatic cord. In individuals assigned female at birth, it continues into the labia majora.[1]

Structurally, the membranous layer is composed of dense collagenous connective tissue reinforced by elastic fibers, providing tensile strength while maintaining flexibility.[1]

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An important anatomical feature is its firm fusion with the fascia lata of the thigh, just inferior to the inguinal ligament. This attachment limits the inferior spread of fluid from the abdominal wall into the thighs.[1]