I bet you hit the knuckle, or base of the shoulder blade. I call it the knuckle. Its right on with that 10 ring and its some of the heaviest bone in that body.

The spine is an option but I am thinking if you hit a whitetials spine coming out of that weight bow, with a 2 blade normally better then good head. You would have busted him up pretty bad given that kind of head damage.

Vs

Smacking the heavier part of the scapula upper leg area. The blood would be bright red due to it being closer to the heart, but yet not the pink frothy lung blood. The real give off is the limp. I really believe with your bow and broadhead setup you would have penetrated the shoulder blade pretty easy and due to where you believe you hit (the 10 ring), that knuckle is right there somewhat in the 10 ring.

What I tell my partners, espically on moose but for all critters is one of two things. If the animal is standing broadside, close leg even with back leg, aim the same distance back way from the shoulder as you would aim up, on a moose 1/3rd up and that same 1/3rd back (not 1/3rd back in animal length). Some get confuzed with this but with a picture its really easy to grasp. The other is aim for the off side leg and only shoot with the close leg forward. This will keep you away from the shoulder blade on critters like moose. It will also depending on the angle allow you to shoot for the top of the heart. IMHO the heart itself is not the thing you want to aim for, its the top of it. You have a better chance of hitting all the veins going to or coming from the heart then the heart itself. But, if you miss it, you will hit lungs and or heart. All of which are good. On a whitetail normally its not an issue, on a moose, it definatly is! Big bones, big hide, huge heart lol.