Third (Intermediate) head of gastrocnemius muscle; a case report and literature review

Abstract

Anatomical variations of limb musculature are common. During the routine dissection for teaching musculoskeletal course for second year students of Medicine, a third (Intermediate) head of the gastrocnemius muscle was detected in a 70-year-old female cadaver in left lower limb. It was originated from the posterior surface of the distal end of the femur by small tendon and extended as long muscular belly. Throughout its course, this belly crosses superficial to the popliteal fossa beneath the skin on its way to join the medial side of the lateral head of gastrocnemius muscle. Furthermore, the intermediate head takes its innervation from the nerve to the lateral head of gastrocnemius that passes on its deeper aspect. No such variation was found in the right lower limb. Knowledge of these variants is very important in clinical practice.

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