Purple Heart

Perhaps one of the most famous of US awards, this was
originally known as the Badge of Military Merit and was instituted by General
George Washington (whose effigy appears on the obverse) in 1782; only three
awards were made. It was a heart-shaped purple velvet badge with silver
embroidered edges. During WW1, small gold chevrons were worn on the right
forearm to denote wounds; a Wound Ribbon appeared but was never officially
approved.
In 1932 the current version of the Purple Heart was introduced and this is
awarded to any member of the US Armed Forces killed or wounded (including
frostbite apparently) in an armed conflict, which includes a terrorist attack,
or being wounded while a prisoner of war. A wound for which the award is made
must have required treatment by a medical officer.