A place where the rounded end of one bone fits into the cup of another bone. Ball-and-socket joints allow movement in two directions, in addition to rotation. (SS, TG)

A joint in which the ball-like end of one bone fits into a cavity, or socket, of another. Human beings have two types of ball-and-socket joints - the hip and the shoulder. Because of their structure, ball-and-socket joints are more flexible than other joints, most of which act like hinges, moving back and forth in one plane.

A synovial joint in which the rounded surface of one bone moves within the cup-shaped depression or fossa of another bone, as in the shoulder or hip joint. Also called a spheroid joint.

joint between rods or links in which ball-like termination fits into concave, spherical socket.