Entrapment of neurovascular structures in the (R) popliteal fossa by the third head of the gastrocnemius

Background: The anatomical arrangement of the structures in and around the gastrocnemius has clinical significance, particularly in understanding surgical and pathological conditions involving the popliteal fossa. Case Description: The present case was reported during the routine dissection of the popliteal fossa in a 50-year-old male cadaver. An extra head of the gastrocnemius was observed on the right popliteal fossa. This additional head extended across the fossa from the lateral to the medial side. Further exploration of the contents of the fossa revealed a very low division of the sciatic nerve. The neurovascular bundle, including the popliteal artery, popliteal vein, and tibial nerve, was found entrapped between the medial head and the third head of the gastrocnemius. Conclusion: Since the literature has recorded very few cases of third head gastrocnemius and popliteal artery entrapment syndromes, this study may help increase awareness of the anatomical variations of the gastrocnemius and the related structures involved.