出典:Wiktionary
ball-and-socket joint (複数形 ball-and-socket joints)
出典:Wikipedia
出典:『Wikipedia』 (2011/07/06 17:20 UTC 版)
A ball and socket joint (enarthrosis, spheroidal joint) is a joint in which the distal bone is capable of motion around an indefinite number of axes, which have one common center. It enables the bone to move in a 360° angle.