q12 - raji_321

[ArchivalUser]

A 31-year-old man presents to the emergency department complaining of pain in the anterior part of his left leg. He first noticed the symptoms while backpacking the day before. Further
examination reveals that the patient has severe weakness when attempting to dorsiflex his toes on the affected side. Plantar flexion of the toes is apparently unaffected. Which of the following is the most likely cause of his symptoms?
A. Compression of the deep peroneal nerve
B. Compression of the femoral nerve
C. Compression of the tibial nerve
D. Partial occlusion of the obturator artery
E. Partial occlusion of the posterior tibial artery

[ArchivalUser]

AAAAA

[ArchivalUser]

A..

[ArchivalUser]

A is CORRECT

The correct answer is A. The patient has anterior compartment syndrome, resulting from fluid accumulation in the anterior fascial compartment of the leg. The increased pressure results in compression of the muscles, blood vessels, and nerves. The major nerves coursing through the anterior compartment include the proximal part of the superficial peroneal nerve and most of the deep peroneal nerve. The deep peroneal nerve innervates the extensor digitorum longus, which extends all the toes except the big toe. Other symptoms may include some paresthesias over the dorsum of the foot (due to compression of the proximal part of the superficial peroneal nerve) and a diminished dorsalis pedis pulse (due to compression of the anterior tibial artery).

Compression of the femoral nerve (choice B) would cause weakness in extension of the knee, as well as paresthesia of the anterior thigh and medial leg.

Compression of the tibial nerve (choice C) would cause weakness in flexion of the toes and loss of sensation from the plantar surface of the foot.

Partial occlusion of the obturator artery (choice D) would diminish blood flow to the medial thigh muscles, possibly affecting adduction of the lower extremity.

Partial occlusion of the posterior tibial artery (choice E) would impede blood flow to the posterior leg and plantar foot.