"[b]What is the OP's definition of shoulder? It has become obvious to me that the definition is not the same to everyone on this thread."[/b]

^^^^
My point in wanting pictures. "Shoulder" is different things to different people. Your description of a disjointed limb is good, as long as it excludes the lower leg.

Shoulder is a large area describing a part of an animal for location. Shoulder joint , as I see it, is the bones and ligaments around the bone ends that include the scapula and humerus.

But to use Angus' terminology, it is the proximal (inside) part that is important to killing the elk. You have to penetrate to the organs beneath and covered by parts of the shoulder, or exposed better by leg movement, to do a quick job of dispatch. Shooting through the shoulder joints - massive balls of bone - makes a mess of bone fragments and bloodshot, and can go awry if the bullet can't penetrate through to the vitals and didn't send sufficient bone fragments to do the job.