Bone Roll
However, after editing the armature, or when using , you may want to set the bone roll.
Reference
Mode
Edit Mode
Menu
Armature ‣ Bone Roll ‣ Recalculate
Hotkey
Ctrl-N
Axis Orientation
Reverse the axis direction.
Shortest Rotation
Avoids rolling the bone over 90 degrees from its current value.
Set
Reference
Mode
Edit Mode
Menu
Armature ‣ Bone Roll ‣ Set
Hotkey
Ctrl-R