ball-and-socket joint

[bawl-uhn-sok-it joint]

noun

1. Also called enarthrosis. Anatomy, Zoology.,  a joint in which the rounded end of one bone fits into a cuplike end of the other bone, allowing for relatively free rotary motion, as at the hip or shoulder.

2. Also called ball joint. a similar joint between rods, links, pipes, etc., consisting of a ball-like termination on one part held within a concave, spherical socket on the other.

ball-and-socket joint

noun

1. a coupling between two rods, tubes, etc, that consists of a spherical part fitting into a spherical socket, allowing free movement within a specific conical volume

2. Also called: multiaxial joint. anatomy a bony joint, such as the hip joint, in which a rounded head fits into a rounded cavity, allowing a wide range of movement

ball-and-socket joint

1. A joint, such as the shoulder or hip joint, in which a spherical knob or knoblike part of one bone fits into a cavity or socket of another, so that some degree of rotary motion is possible in every direction.

2. A mechanical device consisting of a spherical knob at the end of a shaft that fits securely into a socket. Ball-and-socket joints are used to connect parts of a machine that require rotary movement in nearly all directions. Ball-and-socket joints allow the front wheels of a car to be turned by the steering mechanism.

Word History and Origins

Origin of ball-and-socket joint¹

First recorded in 1660–70

Example Sentences

Those fingers come with a long, skeletal middle digit equipped with a ball-and-socket joint for horrifying dexterity, like the Ghost of Christmas Yet to Come beckoning Ebenezer Scrooge to gaze upon his own sordid death.

From Salon

The ball-and-socket joint of the shoulder is secured by the four muscles and tendons of the rotator cuff, which can become irritated, torn or overstretched.

From New York Times

Dr. Günther compares it to a ball-and-socket joint, except there is no socket.

From New York Times

The second shot went through Andrew’s hip and into his ball-and-socket joint, then into his lower abdomen before landing in his right hip, she continued.

From Fox News

Traditionally, the damaged ball-and-socket joint is removed surgically and replaced by one made artificially.

From New York Times