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.
[Continued from above] . . . It begins at the dorsal venous arch of the foot, a major superficial vein that drains blood from the toes and back of the foot. From the dorsal venous arch, the great saphenous vein passes anterior to the medial malleolus of the ankle and enters the medial side of the leg.