The actions of abduction and adduction were previously described with regard to movements relating to the body as a whole. Opposition Opposition is a special action of the hand, whereby the thumb and little finger are brought around to touch the fingertips. This action occurs at the joints between the carpal bones and the metacarpals of the thumb and little finger. Another special action occurs in the forearm, where the radius and ulna are arranged in such a way as to allow the crossing of the distal end of the radius over the ulna. The specialized movements occurring here are pronation and supination.
Pronation is the movement of crossing the radius over the ulna.
This movement results in the dorsal surface of the hand turning forward, or prone. Copyright 1994 University of Michigan Learning Resource Center. For classroom use only. No part of this lesson can be reproduced for commercial use.