Compression of the tibial nerve by the tendinous arch of origin of the soleus muscle.

Details of 5 cases of surgically confirmed entrapment of the tibial nerve in the popliteal fossa are presented. In 4 cases the nerve was compressed beneath the tendinous arch of the origin of the soleus muscle. In 1 of these cases, thrombosis of a tributary of the popliteal vein with oedema of structures in the popliteal fossa and secondary compression of the nerve was found. In the fifth case the popliteal vein was compressed by the soleus arch with secondary compression of the nerve. The clinical presentation in these cases was characterised by severe pain and tenderness in the popliteal fossa, aggravated by active and passive dorsiflexion of the foot, inability to weight bear, and numbness and pain in the sole of the foot and heel. In each case, surgical exploration and division of the soleus arch led to prompt relief of symptoms.