I shot 2 deer this year that hit a little high, right under the spine & they both dropped in sight, maybe 15 to 20 yards & they were down. Dressing them I found I had cut the fat vane just under the spine & out thru the far lung on both deer. They were filled with blood from cutting the vane. Now I dont know because I'v never seen the insides of a living deer but it sure looks like if I hit any lower then I'da got a double lung & any higher I'da got the spine. I cant figure out where this void would be. I think sometimes a shot can go over the spine & fool us. I cant count the tmes I'v been sure of my shot placement only to find a hole where it wasn't supposed to be. Its hard in the field to be sure where your arrow hit. Deer move, angles are misjudged, chit happens, but I dont believe theres an empty place in a deers chest.