I'm not a doctor, but I kind of wanted to be a rodeo cowboy, and experienced a broken bone or two and had the doc point out things in the xray. Looks to me like the arm of the mystery skeleton is backwards, the forearm bones are not in the proper location, they are bass ackwards, and note that the lower leg, between the knee and the ankle, is supposed to be two bones, and this guy only has one. What ever suits you, but it looks hokey to me.
Oops, looked again and it appears he's on his back, so arm is OK, but the solid bone on the lower leg bothers me. In the photo it's kind of like killing a small buck, then sitting way back in the picture, in order to make the buck look bigger. Also, people that can photo shop pictures can work wonders. I still say hoax.