Scarpa fascia is the deep membranous layer of the superficial fascia of the anterior abdominal wall, lying deep to Camper fascia and superficial to the external oblique aponeurosis. It is attached inferiorly to the fascia lata of the thigh along a line parallel to and below the inguinal ligament, preventing fluid extravasation from the perineum into the thigh (but allowing it to spread superiorly into the abdominal wall). It is continuous with Colles fascia in the perineum.
Forms a membranous fascial barrier between the abdominal wall and the thigh, containing fluid extravasation from perineal pathology within the perineal/abdominal compartment, and defines the superficial surgical plane for abdominoplasty flap elevation.
Scarpa fascia is the landmark for abdominoplasty and lower abdominal surgery: the abdominoplasty flap is elevated in the plane between Scarpa fascia and the deep muscular fascia (external oblique aponeurosis), preserving the lymphatics and reducing lymphoedema risk. Urethral injury with extravasation below Scarpa fascia collects in the perineum and spreads to the scrotum and lower abdominal wall (but not the thighs) due to Scarpa fascia's femoral attachment. In inguinal surgery, the Scarpa fascia is encountered just below the skin incision.
Bulbar urethral rupture below Scarpa fascia allows urine extravasation into the perineum spreading to the scrotum and lower abdominal wall superficially but not into the thighs (contained by Scarpa's femoral attachment), producing the classic perineal butterfly haematoma pattern managed by suprapubic catheter and urethral repair.
