Never undescribed before, four-headed plantaris muscle.

The plantaris is a small muscle of the superficial posterior compartment of the leg. It originates at the lateral supracondylar line of the femur and the knee joint capsule, from where it continues distally, forming a long and slender tendon distally attached to the calcaneal tuberosity. During standard anatomical dissection a four-headed plantaris muscle was found, and all of its heads connected to each other as a single muscle belly passing into tendinous structure, which was distally attached as a standard plantaris muscle. The first head originated from the popliteal surface of the femur. The second one originated from distal Kaplan fibre. The third and fourth heads were proximally attached to the lateral femoral epicondyle. Knowledge about morphological variations is necessary because of its potential clinical significance, which means not only neurovascular compressions, but also surgical procedures.