Where is the insertion of the popliteus muscle located?

The insertion of the popliteus muscle is located on the posterior aspect of the tibia, specifically in a groove above the soleal line. This muscle plays a critical role in stabilizing the knee and helping to unlock it from a fully extended position. It works by laterally rotating the femur on the tibia when the leg is fixed, or medially rotating the tibia on the femur when the leg is not bearing weight.

The other options do not serve as the insertion for the popliteus muscle: the fibula and humerus are anatomically distinct bones that are not associated with the popliteus. The long tendon of the Achilles is related to the gastrocnemius and soleus muscles, not the popliteus. Therefore, identifying the correct anatomical attachment point is essential for understanding the functional implications of the popliteus in movement and stability of the knee joint.