from The Century Dictionary.
- noun In anatomy, a ball-and-socket joint; a kind of movable arthrosis or free articulation which consists in the socketing of a convex end of a bone in a concavity of another bone, forming a joint freely movable in every direction. The hip and shoulder are characteristic examples. Also
from the GNU version of the Collaborative International Dictionary of English.
- noun (Anat.) A ball and socket joint, or the kind of articulation represented by such a joint. See
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun anatomy A
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- noun a freely moving joint in which a sphere on the head of one bone fits into a rounded cavity in the other bone
from The American Heritage® Dictionary of the English Language, 4th Edition
The bony surfaces would of themselves constitute an enarthrosis and allow of movement in all directions, were it not for the annular ligament, by which the head of the radius is bound to the radial notch of the ulna, and which prevents any separation of the two bones laterally.
The incudostapedial joint is an enarthrosis, surrounded by an articular capsule; some observers have described an articular disk or meniscus in this joint; others regard the joint as a syndesmosis.
There is one form where the movement is polyaxial, the enarthrosis or ball-and-socket joint; and finally there are the arthrodia or gliding joints.