Well I thought I was done with this but I was wrong. Do me a favor. Ask a doctor, vet, biologist, Obama or Jesus I dont care who but ask some one you know and trust to explain a little anatomy101. 1. Animals such as humans or deer are pretty efficient creatures. There is not really any left over space inside the body. When we/they were created someone really knew what they were doing. Every little bit of space is used. 2. When an animal breathes the chest shrinks and expands with the lungs. This is what kills the idea of the projectile passing through while the animal is exhaling. 3. The chest cavity more specifically the pleural cavity is under a slight vacuum. This is what keep the lungs expanded and full in the chest. 4. When air is introduced to this cavity it is known as a Pneumothorax. That is bad. It can cause some seriuos health problems. 5. The only way air could be intorduced to this cavity is if there is a void or the lung was deflated by something like an arrow or bullet. As I already explained, there are no voids in the body. 6. The lungs sit higher than any other organ in the deer. Since I alreay explained that there is no extra room or voids in the body it should be pretty easy to understand that there is nothing between the lungs and the vertebrae but lung. 7. There simply is no way to send a sharp broadhead or a speeding bullet through this cavity without connecting with the lungs. I understand you believe what you think you saw but you are mistaken.