popliteus (muscle)

pop·li··te·us (mus·cle)

[TA]
muscle forming floor of popliteal fossa; origin, lateral condyle of femur; insertion, posterior surface of tibia above oblique line; action, from the fully extended and "locked" position, rotates the femur medially, on the fixed (planted) tibial plateau about 5°, "unlocking" the knee to enable flexion to occur; nerve supply, tibial.