Internal anatomy of deer
Bow hunters should choose a spot in the center of the lungs or slightly lower to be their target every time. An arrow in the lungs will bring down the largest game, and the advantage of this shot is that the lungs are relatively large and surrounded by other vital organs: the heart is below, the spine and aorta (a major artery) are above, and the liver and the spleen are behind.
Hunters using firearms have many more choices than bow hunters. A bullet striking either the heart, shoulder, head, spine or lungs is fatal to big game animals due to the massive shock and tissue destruction involved. Once again, the chest area offers the best lethal target.