Age / Sex : 14 / M

Chief complaint : 5일전 바지입다가 넘어지면서 right foot drop 증상발생함

What is your diagnosis?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).


Courtesy : 이승훈 한양대학교병원, Lee Seunghun, Hanyang University Hospital

common peroneal neuropathy

Discussion

Findings: At the knee joint the proximal portion of the peroneal nerve is relatively large, and increased SI on T2W scans. Another findings include denervation edema and atrophy of both the anterior compartment and the lateral compartment of lower leg.

Differential Diagnosis: NA

Discussion: In general, common peroneal neuropathy occurs in the knee region, whereas neuropathy of the two main branches of the common peroneal nerve develops more distally at the leg, ankle, or foot. Common peroneal neuropathy is the most common mononeuropathy in the lower extremity. The common peroneal nerve is superficial in the knee area and is fixed in position around the fibular neck and in the peroneal tunnel. These factors predispose it to extrinsic compression, often surgically related, and to direct trauma. Foot drop, often acute, with weak foot extension, weak foot eversion, weak toe extension, and loss of sensation in the lower lateral two thirds of the leg and dorsum of the foot may develop.

References:

David W. Stoller, MD, FACR. 3rd edition. Magnetic resonance imaging in orthopaedics and sports medicine 1993, 3rd edition.