of the anterior sheath. This incision allows the recti to approximate, and once more to lie in the position Nature intended for them. T h e posterior sheath arises from such a length of muscle, encircling almost Displacement of anterior sheath Site of medial incision Site of lateral /incision Knife cut opened out-\\ / L Displacement of posterior sheath by stretching of long muscle attachment -Rib , margin FIG. 58g.-Diagram showing anatomy of the posterior sheath.the entire abdominal cavity, that it exerts no restraining influence in this inward movement (Fig. 589).Gibson has remarked that "the surprising feature i n the after-result of these cases is the lack of weakness of the abdominal wall where the fascia gapes as a result of being pulled away". Immediately after the operation, however, the lateral weak spot is covered not only by thinned-out muscle, but posteriorly has the internal oblique and transversus muscle fascia as a firm support. In m y series there is only one case of herniation through this area (see Table I ) . Recently I had to perform a cholecystectomy on a patient for whom I repaired an epigastric incisional hernia seven years ago, using the technique described above. At operation it was found that the anterior sheath had grown over the bare muscle gap in a thin but definite layer, and the rectus muscle appeared to be of normal thickness. SUMMARY A method of repair of epigastric incisional hernia is offered, with an anatomical explanation for its effectiveness.