I don't know if I would really call it a void. My experience was gutting a bull I had killed with rifle. As I was gutting it, I noticed what I thought was a stick laying close to the spine (bull was on its back). I grabbed it and felt it was attached (by soft tissue) and realized it was an arrow. I pulled it loose and found about 9-12" of arrow with a 3 blade broadhead like a G5. The broadhead was covered in scar tissue. Entrance was 4-6 ribs from the back, and it broke a rib going in and then stopped against a rib on the other side. The bull was young, a 4 point, and was running a herd of a dozen cows. I hunted him off and on for 2-3 days. He was completely fine.
I've probably cleaned and quartered 100+ elk over the years, and I, for the life of me, cannot explain it. There is a huge artery against the spine, and the lungs go right up against that.
My only guess is the broadhead was really dull and whatever tissue it came into contact with as it went through the bull didn't get cut.
I saw another picture last week of a similar hit, but it was really far forward. At the very front of the thoracic cavity. Which makes even less sense.
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