A 12-year-old boy is brought to the physician by his father because of redness and swelling of his left foot for 24 hours. Three days ago, the boy scraped his foot while wading in a drainage ditch. Examination of the left foot shows a purulent abrasion with edema, erythema, and tenderness on the lateral side. Infection is most likely to next spread from the lateral side of the foot to the regional lymph nodes in which of the following areas?
(A) Lateral surface of the thigh
(B) Medial malleolus, posteriorly
(C) Popliteal fossa
(D) Sole of the foot
(E) Superficial inguinal area
Correct answer: (C) Popliteal fossa
The superficial lymphatic vessels of the lower limb are arranged as medial trunks, which end in the superficial inguinal nodes, and as a lateral set, which ends in the popliteal nodes. The popliteal nodes receive the deep lymphatic trunks that accompany the tibial blood vessels and the lateral group of superficial trunks. Their efferents accompany the femoral blood vessels to the deep inguinal nodes.
Explanation contributed by Raja Muthusami. If you like to publish a question here, just email the question with correct answer and suitable explanation to pgblazerofficial (at) gmail (dot) com.