In part 1 of this series we looked at the passive structures in human anatomy that are relevant to the knee joint (Anatomy of the knee – part 1: passive structures). In this post we will investigate the active stabilizing structures surrounding the knee. On the front of your body this would be the quadriceps and on the back it’s the hamstrings, gastrocnemius, as well as the popliteus. Let’s get acquainted with the quads first.