The gastrocnemius is a large, superficial calf muscle originating from the femoral condyles and inserting into the calcaneus via the Achilles tendon, primarily responsible for plantarflexion of the foot and knee flexion. Clinically, its function is critical for walking, running, and maintaining posture, and it is commonly involved in strains or tears, especially in athletes. A key complication related to the gastrocnemius is a muscle tear that can cause sudden calf pain and impair mobility, often referred to as a “tennis leg.”