Peritonitis is defined as inflammation of the peritoneum. The inflammatory response involves vasodilation, exudation of protein-rich fluid, cellular infiltration, pain and, chronically, formation of fibrous adhesion. The disease can be classified into primary and secondary cases.
It begins in the venous plexus along the medial side of the foot, and it runs up the medial side of the leg and knee, alongside the saphenous nerve. In the thigh, the long saphenous vein continues up the medial surface, accompanying the medial femoral cutaneous nerve.
At the top of the thigh, it passes through the saphenous opening of the fascia lata and enters the deeper tissues of the upper thigh before merging into the femoral vein. An extensive network of superficial veins connects to the great saphenous vein throughout its length.