What are Articular Surfaces?

Hi,
I was wondering if anyone could explain what articular surfaces are on horses .thanks

The way I understand it:
Articular - think of articulation -- where there is movement, therefore at a joint

So the articular surface is the surface area of the joints where the movement occurs. Whether in horses, people, or machines.

The articular surface is the part of the bone that is located inside the joint. It usually has cartilage on the bone end and the surface is lubricated with joint fluid. It is here that arthritic changes take place and interfere with smooth 'pain free' movement of the joint in question.