A man is sitting on a chair. He brings himself up into a standing position. His tibiofemoral joint moves from a flexed position to full extension during the maneuver

Which of the following best describes what is happening at the tibiofemoral joint during this maneuver? Think in anatomical terms.
a. Anterior glide of the proximal tibia on the distal femur
b. Posterior glide of the proximal tibia on the distal femur
c. Anterior glide of the distal femur on the proximal tibia
d. Posterior glide of the distal femur on the proximal tibia

ANS: D
The activity of rising from a chair would be a closed kinematic chain activity, which means that
the proximal joint surface will be moving on the distal joint surface. In the case of the tibiofemoral
joint, this means that the convex femoral condyles will move on the concave tibial plateau.
Because this would constitute a convex surface moving on a concave surface, the roll and glide of
the joint surfaces will occur in opposite directions. As the person comes to a standing position, the
femur will roll in an anterior direction, and the joint surface will glide (or slide) in a posterior
direction.