human) head. face is used when referring to physical features: a pretty face with high cheekbones. countenance, a more formal word, denotes the face as it is affected by or reveals a person's state of mind; hence, it often signifies the look or expression on the face: a thoughtful countenance.
Muscles Around the Knee. 1  Quadriceps femoris musclesâa large muscle group on the front of the thigh. 2  Vastus lateralisâpart of the quadriceps femoris on the outside-front of the thigh, it extends or straightens the leg and is controlled by the femoral nerve. Vastus lateralisâpart of the quadriceps femoris on the outside-front of the thigh, it extends or straightens the leg and is controlled by the femoral nerve. 2  Vastus intermediusâpart of the quadriceps femoris on the center-front of the thigh, it extends or straightens the leg and is controlled by the femoral nerve.
Anterior Cruciate Ligament (ACL) Tear. The Anterior Cruciate Ligament (ACL) is a strong ligament inside the knee that connects the thighbone (femur) to the shinbone (tibia). It may become torn, resulting in instability of the knee. Falls that cause the knee to twist or pivot. Rapid deceleration or pivoting in sports.