The popliteus muscle is a band of muscular tissue located in the leg.

The muscle wraps around the bottom half of the femur, or thighbone. It inserts on the back of the shinbone, or tibia, and runs through a bony projection at the bottom of the femur known as the lateral condyle of the femur.

There are two other points of attachment. The muscle’s tendon is connected to the popliteal sulcus on the thighbone. One subsection of the muscle also originates from the fibula, or calf bone. Its tendon reaches the knee capsule and wraps around the knee joint.

The muscle is thin and flat, with a triangular shape that spans the femur and knee. The popliteal fossa, an open space at the back of the knee joint, is extended over the popliteus muscle.

The popliteus muscle provides the knee with an added degree of mobility. With the muscle, the knee is able to rotate within the body by prompting the femur to turn on top of the tibia. Standing requires the least amount of activity from the popliteus muscle.