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.
After exiting the femoral triangle, the femoral artery continues down the anterior surface of the thigh, via a tunnel known as the adductor canal. During its descent the artery supplies the anterior thigh muscles. The adductor canal ends at an opening in the adductor magnus, called the adductor hiatus.