Old York,what most refer to as the shoulder in a deer is about the same as the front quarter.It is the upper leg and the mass of muscles covering the scapula or shoulder blade. With archery gear,we are trying to avoid hitting the scapula and upper leg bone.See Guru's diagram.If you draw a line from the elbow,to a point about 3/4 of the way up the scapula,that would be the back edge of the tricep or back of the upper leg.Most aim just behind that line. We are just trying to get an arrow into the heart and lungs without risking hitting the scapula and humerus,which often will stop an arrow. ChuckC,the joint end of the scapula moves more than the upper,wide end.It moves forward to about a 45 degree angle but can go farther if the front leg is stretched way forward in a leap.It can rotate back to about a straight up and down position when the front leg is all the way to the rear.The wide end stays close to it's position beside the shoulder hump and the joint end of the scapula moves a lot more.I'm guessing the shoulder joint probably travels 6" or more,in a forward or back motion.