ball-and-socket joint


Definition of ball-and-socket joint

1 : a joint in which a ball moves within a socket so as to allow rotary motion in every direction within certain limits
2 : an articulation (such as the hip joint) in which the rounded head of one bone fits into a cuplike cavity of the other and admits movement in any direction

Illustration of ball-and-socket joint

Illustration of ball-and-socket joint

ball-and-socket joint 1

Examples of ball-and-socket joint in a Sentence

Recent Examples on the Web The seven vertebrae in her neck—the same number as in a human’s—are connected by ball-and-socket joints like those in our shoulders, so instead of lifting up like a rigid beam, her neck snakes upward in an almost reptilian way. Ed Yong, The Atlantic, "The Last Giraffes on Earth," 13 Mar. 2020 Its third digit, which is primarily used for tapping, is very thin and has a wide range of motion, equipped with a unique ball-and-socket joint. National Geographic, "This bizarre primate has a newly discovered digit," 21 Oct. 2019 The latching system is based on a ball-and-socket joint. Martin Finucane,, "In the future, Amsterdam’s canals might have robot boats," 6 June 2019 Unlike a hinge joint that moves only (for the most part) forward and backward, like the knee, the shape of the ball-and-socket joint in the hip allows for flexion, extension, internal and external rotation, abduction, and adduction. SELF, "5 Lunges Everyone With Tight Hips Should Do," 22 Feb. 2019 And your shoulders specifically may benefit immensely from rotator cuff exercises, which strengthen and stabilize the small muscles that help keep the ball-and-socket joint in place. Amy Marturana, SELF, "12 Stretches to Relieve Tight Shoulders," 2 Nov. 2018 The ball of this ball-and-socket joint had been flattened by wear and tear, and its no-longer-smooth surface was now in direct contact with the bony cup of the socket. Lisa Sanders, New York Times, "The Patient Had Pain When He Walked, but There Was a More Telling Change," 27 June 2018 And this finger is articulated by sitting on a ball-and-socket joint, allowing it to move and swivel a full 360 degrees. Ralph Steadman, Discover Magazine, "Where the Wild Things Aren't," 1 Mar. 2018 For example, a hinge has one degree of freedom while a ball-and-socket joint has three. James Gorman, New York Times, "How It Works: The Large Mouth of the Largemouth Bass," 26 Dec. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ball-and-socket joint.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of ball-and-socket joint

1779, in the meaning defined at sense 1

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Time Traveler for ball-and-socket joint

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The first known use of ball-and-socket joint was in 1779

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Cite this Entry

“Ball-and-socket joint.” Dictionary, Merriam-Webster, Accessed 19 Jan. 2021.

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More Definitions for ball-and-socket joint

ball-and-socket joint


Kids Definition of ball-and-socket joint

: a joint (as in the shoulder) in which a rounded part can move in many directions in a socket

ball-and-socket joint


Medical Definition of ball-and-socket joint

: an articulation (as the hip joint) in which the rounded head of one bone fits into a cuplike cavity of the other and admits movement in any direction

called also enarthrosis

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