Aberrant popliteus muscle: anatomy and clinical consideration.

The aberrant popliteus muscle is an anomalous muscle in the popliteal fossa. It originates from the femur in the superior triangular surface of the popliteal fossa above the origin of the gastrocnemius muscle and it is inserted into the musculo- tendinous part on the medial side of the lateral head of the gastrocnemius muscle. The muscle lies immediately deep to the popliteal vein and during contraction is likely to compress the popliteal vein and reduce venous return from legs; it could also compress the lateral branches of the popliteal artery to the knee joint and the lateral head of the gastrocnemius muscle. It may present as a tumour of the popliteal fossa in radiographic examinations such as computed tomography (CT) and magnetic resonance imaging (MRI). If it undergoes hypertrophy as it may do in athletes and body builders, it may limit flexion of the knee joint, cause pain due to compression of surrounding structures and inhibit performance.