A patient develops a swollen and tender lymph node in his popliteal fossa. An infected skin lesion in which of the following sites would most likely induce lymphadenopathy in this region?

Most of the venous drainage of the skin of the lower extremity is to the long saphenous vein, the accompanying lymphatics of which drain into the superficial group of the inguinal lymph nodes. However, the skin drained by the sho saphenous vein, including that of the lateral aspect of the dorsum of the foot, is an exception to this rule. Lymphatic fluid from this area drains into lymphatics accompanying the sho saphenous vein, then drains into lymph nodes behind the knee in the popliteal fossa.The lateral side of the thigh , the medial side of the leg below the knee and the medial side of the sole of the foot all drain to the superficial inguinal nodes.