Assertion: knee's joint | /r/CapableOf | allow flexion
Facets:
Source sentences:
text: Hinge joints allow flexion and extension only.
text: The medial and lateral tibiofemoral joints, between the condyles of the femur and condyles of the tibia, are modified hinge joints that allow for knee extension and flexion.
text: The joint allows flexion, extension and even rotation of the lower leg till some extend.
text: Going back to the terminology from last week, the hinge joint allows flexion and extension.