The abdominal walls are composed of the skin, superficial fascia, muscles, trans-versalis fascia, subperitoneal tissue, and peritoneum.


The skin of the abdomen is moderately thin and lax. It is adherent at the linea alba. In making incisions care is to be taken not to think it thicker than it is and so open the abdominal cavity and perhaps wound the intestines. This is especially liable to occur in the median line - where the subcutaneous fat is not so abundant as elsewhere - and over hernial protrusions, particularly umbilical, where the thinned and distended skin may lie in contact with the peritoneum.

Superficial Fascia

The superficial fascia is composed of an upper fatty layer, and a lower fibrous layer called Scarpa's fascia. The superficial vessels run on this fibrous layer but are too small to cause troublesome hemorrhage; a few minutes' compression with haemostatic forceps serves to stop bleeding from them. This layer is attached at the linea alba, but not sufficiently closely to prevent extravasated urine from crossing and reaching both flanks. It is also attached to the fascia lata just below Poupart's ligament, and here it does prevent urine from passing downward on the thigh. It passes inward over the spermatic cord and is continuous with the dartos of the scrotum and its septum. It is attached to the spines of the pubes and to the symphysis in the median line. This leaves a space or abdomino-scrotal opening over the pubic bone on each side of the median line through which extravasated urine rises from the perineum and scrotum to reach the surface of the abdomen.