The shoulder and hip joints are the only ball-and-socket joints in the human body due to the need for great motion at the end of the body's limbs and the vast amount of musculature needed to move and support such flexible joints.

What is an example of a socket joint?

Examples of this form of articulation are found in the hip, where the round head of the femur (ball) rests in the cup-like acetabulum (socket) of the pelvis; and in the shoulder joint, where the rounded upper extremity of the humerus (ball) rests in the cup-like glenoid fossa (socket) of the shoulder blade.

What is a socket joint?

socket joint in British English

(ˈsɒkɪt dʒɔɪnt) 1. engineering. a joint in which the rounded end of one part fits into the cavity of another part. The round socket joint into the seat provides a rotational movement which helps in obtaining a correct alignment.