Baker's cysts as a clinical entity are among the most infrequent cause
of peripheral nerve entrapment and usually produce a strong positive
pressure within the knee resulting in the rupture of the joint capsule
. An unusual case with muscular and sensorial weakness due to compress
ion of the peroneal nerve around the fibular head by a Baker cyst is p
resented in this article. Clinical and electromyographical findings sh
own peroneal nerve entrapments in the popliteal fossa. Peroneal nerve
decompression by synevectomy resulted in clinical and electromyographi
cal improvement.