Good lesson, shoot about 4 inches back from where you hit. I can't find a good picture on the net to post here but the cervical vertbrae in the neck drop down and are very low toward the front of the chest cavity. Looks to me this is where you hit this deer.
The picture is deceiving because of how the deer is laying in the photo. The head is pushed back and the fore limb is pushed forward. This hole would appear to be in a different place were that deer standing. Topographical anatomy is very importatant, anatomy related to looking at the outside of the animal. It is much different than a dead deer hanging in a tree being skinned and cut up.
The vertebrae are much lower than most people think. The farther toward the front of the deer the lower they are located. They come down off the skull and are almost at the lowest point in the neck where the chest cavity starts. When they enter the chest and become the thoracic vetebrae they actually curve back up toward the topline of the deer.