The term "short-arm inspection" is a military euphemism referring to the routine medical inspection of male soldiers' penises ("short arms") for signs of sexually-transmitted diseases and other medical problems.[1]
The precise origin of the term is uncertain; however, American[2] and Australian troops are known to have used the term during the First World War.[3]
The practice within the Imperial Japanese Army during World War 2 was described by an anonymous American soldier, who had been forced to work as a truck driver while held as a prisoner of war, and who came into daily close contact with Japanese soldiers.[4]
When a Jap G.I. turns in with a venereal disease, he gets a good beating and loses what few privileges have been allowed to him. For this reason, they go to civilian doctors or to drug stores, and try to doctor themselves. Many of them are infected. Short-arm inspection is held only on rare occasions. In fact, there was only one such inspection during the time I was a prisoner.
— American, former prisoner of war (1945)