Popliteus

[Kai]

a thin muscle at the back of the knee that bends the leg and rotates the femur (= the long bone in the upper part of the leg)

[Julene]

A flat muscle at the back of the knee which arises from the lateral condyle of the femur and is inserted into the posterior surface of the tibia, and serves to rotate the tibia on the femur, allowing the fully extended knee to begin flexion.