The deltoid muscle is the triangular muscle that covers the upper arm and shoulder joint. It moves the upper arm forward, backward, to the side, and away from the body.
Primary Medical ReviewerWilliam H. Blahd, Jr., MD, FACEP - Emergency Medicine
Specialist Medical ReviewerPatrick J. McMahon, MD - Orthopedic Surgery
Current as ofNovember 14, 2014
WebMD Medical Reference from Healthwise