
This is worth at least a thousand words.
Honestly though, I don't think the sprite needs to be 100% anatomically accurate. Get the basic forms right, and I think the rest can be artistic interpretation. If some definition is in the wrong place, it's not really hurting the message the sprite is communicating. The point is, he's a beast, and your sprite conveys that well.
I also echo Mathias' suggestion. If you make the arms move at a different rate than the rest of the torso, it will add depth to the sprite. Otherwise it looks like his arms are stuck to his torso. Some fighting game idle loops illustrate this principle well. You could try making his arms bounce 2 pixels when his torso bounces 1, or delay the arms so when the torso rises, the arms stay low for a frame before they catch up (then when his torso lowers, his arms stay up for a frame). Make sense?