What is the bending of a limb or joint; that motion of a joint which gives the distal member a continually decreasing angle with the axis of the proximal part; -- distinguished from extension called?

flexion — (Physiol.) The bending of a limb or joint; that motion of a joint which gives the distal member a continually decreasing angle with the axis of the proximal part; -- distinguished from extension. (Webster's 1913.)

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