Superficial Fascia

The superficial fascia is divided into two layers: a more superficial fatty layer (Camper’s fascia) and a deeper membranous layer (Scarpa’s fascia) (Fig. 6.8). The fatty layer is continuous with the superficial fat over the rest of the body and may be extremely thick (3 in. [8 cm] or more in obese patients). The membranous layer is thin and fades out laterally and above, where it becomes continuous with the superficial fascia of the back and the thorax, respectively. Inferiorly, the membranous layer passes onto the front of the thigh, where it fuses with the deep fascia one fingerbreadth below the inguinal ligament. In the midline inferiorly, the membranous layer of fascia is not attached to the pubis but forms a tubular sheath for the penis (or clitoris). Below in the perineum, it enters the wall of the scrotum (or labia majora). From there, it passes to attachments on each side to the margins of the pubic arch; it is here referred to as Colles’ fascia. Posteriorly, it fuses with the perineal body and the posterior margin of the perineal membrane

Figure 6.8 Arrangement of the fatty layer and the membranous layer of the superficial fascia in the lower part of the anterior abdominal wall. A. Anterior view. Note the line of fusion between the membranous layer and the deep fascia of the thigh (fascia lata). B. Sagittal view. Note the attachment of the membranous layer to the posterior margin of the perineal membrane. Arrows indicate paths taken by urine in cases of ruptured urethra. In the scrotum, the fatty layer of the superficial fascia exists as a thin layer of smooth muscle, the dartos muscle. The membranous layer of the superficial fascia persists as a separate layer.

Membranous Layer of Superficial Fascia and Extravasation of Urine

The membranous layer of the superficial fascia is important clinically because beneath it is a potential closed space that does not open into the thigh but is continuous with the superficial perineal pouch via the penis and scrotum. Rupture of the penile urethra may be followed by extravasation of urine into the scrotum, perineum, and penis and then up into the lower part of the anterior abdominal wall deep to the membranous layer of fascia. The urine is excluded from the thigh because of the attachment of the fascia to the fascia lata (see Fig. 6.8).

When closing abdominal wounds, a surgeon usually puts in a continuous suture uniting the divided membranous layer of superficial fascia. This strengthens the healing wound, prevents stretching of the skin scar, and makes for a more cosmetically acceptable result.

Deep Fascia

The deep fascia in the anterolateral abdominal wall is merely a thin layer of connective tissue covering the muscles. It lies immediately deep to the membranous layer of superficial fascia.