Switch X and Y axis bone

Hi,

Is it possible to switch the X and Y axes of a bone in blender?
In the following picture you can see that the y-axis points up and the x-axis points right. http://upload.wikimedia.org/wikipedia/commons/3/30/Axis_drawing.jpg

I want to switch the X and Y axes so that the X-asis points up and the Y-axis points right (Z-axis points backwards). Is this possible in Blender?

press ctrl N

If you change the roll with ctrl N, the Y-axis stays in the direction of the bone.