After creating your skeleton, you may notice one or two missing joints. For example, after creating the upper body of a human skeleton, you might want to add collar bones between the skeleton root and shoulder.
To add bones to a skeleton:
For example, if you are adding a collar bone between the skeleton root and the shoulder bone, you would drag the new Skeleton node to the skeleton root, making the root the parent of the new node.
For example, you would drag the Shoulder bone (including its children) to be a child of the new collar bone in the above example.