Sciatic nerve entrapment in the popliteal fossa: a case report

Variations among the posterior compartment muscles of the thigh are uncommon. In 1998, Somayaji et al [1] reported a muscle which originated from the semimembranosus and biceps femoris muscles and then inserted in to the superficial surface of the tendo calcaneous. According to Barry and Bothroyd [2] extra slips of origin associated with gastrocnemius and soleus usually join those muscles or the tendo calcaneus. Parsons [3], reported about a muscle slip that passed transversely between the two heads of origin of gastrocnemius. Insertion of muscle slips from biceps femoris into gastrocnemius and into the tendo calcaneus have been reported [4]. In this report, we discuss an anomalous muscle in the popliteal fossa with a difference in its origin and insertion from the muscles mentioned above. We also discuss in this context, the possible compressive neuropathies caused by such variant muscles.