They an divided into hinge joints, ball-and-socket joints and pivot joints.
"A Practical Physiology" by Albert F. Blaisdell
It is a bath that can be rocked, or inclined in any direction, for its center rests upon a ball-and-socket joint.
"Scientific American Supplement, No. 315, January 14, 1882" by Various
It has a large round head, which is received into the acetabulum, thus affording a good illustration of a ball and socket joint.
"The People's Common Sense Medical Adviser in Plain English" by R. V. Pierce
They were mostly metal backbone and a series of tanks, with rocket motors mounted on ball and socket joints.
"Space Tug" by Murray Leinster
Yes, John, it reminds us of the ball-and-socket joint, only this is a hinge joint, and does not move in so many directions.
"The Insect Folk" by Margaret Warner Morley
Ball and Socket Joints.
"Practical Mechanics for Boys" by J. S. Zerbe
Cotyla: the articular pan; the cup or socket of a ball and socket joint.
"Explanation of Terms Used in Entomology" by John. B. Smith
The neck was set with ball and socket as though the huge head were upon a universal joint.
"Astounding Stories, May, 1931" by Various
The ball and socket joints, as the shoulder, are not limited to mere flexion and extension.
"A Treatise on Anatomy, Physiology, and Hygiene (Revised Edition)" by Calvin Cutter
The bones of the spine were connected by ball and socket joints, and the heads were movable.
"Earth and Sky Every Child Should Know" by Julia Ellen Rogers
ARTHRO'DIA, a species of articulation, in which the head of one bone is received into a shallow socket in another; a ball-and-socket joint.
"The New Gresham Encyclopedia. Vol. 1 Part 2" by Various
It is covered with movable spines articulated by ball-and-socket joints.
"The New Gresham Encyclopedia" by Various
Supported on a tripod by means of a ball-and-socket joint and screw-tightening device.
"Early American Scientific Instruments and Their Makers" by Silvio A. Bedini
The SHOULDER JOINT is a good example of the ball and socket or enarthrodial variety.
"Encyclopaedia Britannica, 11th Edition, Volume 15, Slice 5" by Various