From the National Archives:
Union Maj. Henry Barnum received a bullet wound to his groin at the Battle of Malvern Hill on July 1, 1862. Left for dead, he was captured and exchanged for a Confederate prisoner of war. While still recovering, Barnum returned to the Union Army, fought at the Battle of Gettysburg and was wounded again at Lookout Mountain. This “Surgeon’s Certificate” from his pension application describes his condition 12 years after receiving the initial wound. […]
Henry Barnum of the 12th Infantry included this photograph in his pension application. Taken decades after the war, it shows the former soldier in uniform with a still-unhealed wound and drainage tube.