Lateral Gastrocnemius Bursa

bursa musculi gastrocnemii lateralis

The lateral gastrocnemius bursa lies between the lateral head of the gastrocnemius and the posterior lateral femoral condyle. It is the lateral equivalent of the medial gastrocnemius bursa but less commonly communicates with the knee joint. It may become distended in posterolateral knee effusion, lateral meniscal pathology, or lateral compartment synovitis.

Region: Knee

Clinical Relevance

Clinical Notes

The lateral gastrocnemius bursa is a potential contributor to posterolateral knee pain and swelling. Unlike the medial gastrocnemius bursa (which commonly communicates with the knee joint to form Baker cysts), the lateral bursa less frequently communicates with the joint. Isolated lateral gastrocnemius bursitis produces posterolateral knee swelling that can be confused with lateral meniscal cyst or posterolateral corner pathology. Ultrasound differentiates the bursa from a meniscal cyst by demonstrating its position proximal to the joint line between the lateral gastroc head and the femoral condyle.

Pathology

Common Injuries & Conditions

Lateral Gastrocnemius Bursitis Mimicking Lateral Meniscal Cyst

Distension of the lateral gastrocnemius bursa produces a posterolateral knee mass at the lateral gastroc head level, distinguishable from a lateral meniscal cyst by its position proximal to the joint line and without communication with the lateral meniscus on MRI; aspiration and corticosteroid injection resolves the bursitis.