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.
The dorsal venous arch in the foot is located at the point where the first and fifth digit dorsal veins run into the small and great saphenous veins. This superficial vein connects the great and small saphenous vein. This arch helps drain deoxygenated blood from the foot. The dorsal metatarsal veins also give the arch blood.