Extrude bone from extruded bone I'm making a model for a person, and I need to do the upper/lower arm. I already extruded a bone from the spine for the upper arm, but when I extrude a bone from the upper arm, It also extrudes a bone from the spine. Can someone help?
The bone which head is selected will be extruded. While selecting the already extruded bone, the bone from which you have extruded remained selected.

How to:
In Edit Mode:
Deselect everything 
Select bone head, which you want to extrude.
Extrude
Deselect everything
and so forth...