Flexion is movement to the front
Extension is movement to the back
Lateral Rotation is also referred to as External Rotation
Medial Rotation is also referred to as Internal Rotation
Note: there seems to be a contradiction in terms when talking about flexion/extension of the knee! Because the muscles that move the lower limb below the knee are in the posterior and therefore flexion and extension are with respect to these muscles.
Pronation is a rotation in the direction of thumbs down
Supination is a rotation iin the direction of thumbs up