male human skeleton knee bone muscle anatomy. 3d render

knee joint formed femur thigh bone tibia shin patella kneecap ends bones covered articular cartilage smooth glide movement surrounded muscles together support stabilize joint key involved movement stability four front extend knee include rectus femoris lateralis intermedius medialis hamstrings: three back flex hip biceps semitendinosus semimembranosus muscle calf works plantarflex foot pushing downward popliteus: small helps unlock initial stages flexion