Here's my study of the upper arm's bones. The upper arm only has the one bone but there's all those little treats in the shoulder keeping it in place and protecting it too. One thing that stuck to me in my study was that the socket that the head of the humerus sticks into points out, forward, and up a little so your shoulders are always pointing forward. The humerus is roughly two scapula or sternum lengths. That'd make it roughly the length of the ribs then, right? Well, hope you learned something and thanks for stopping by. Come again!