Each joint surface has a convexity at right angles to a concave surface. All movements except rotation are possible at this joint. Example: first carpometacarpal joint (thumb).
A synovial joint where one element is concave and the other convex, like the joint between the thumb and the wrist.
Articular surface where double motion is due to the concave surface of one joint interacting with the convex surface of another; for example, the carpal and metacarpal of the thumb.
A joint in which the opposing surfaces are reciprocally concavoconvex.