Twist Skeleton Joint around it's axis.
Click and drag the 3D cursor near to the node at the end of the Joint to be twisted. Hold down the left mouse button and click the right button to select the node. Drag the mouse (keeping the left button pressed) to pivot the local nodal axes around the Joint's Axis. Release the left button when the axes are in the desired direction. The directions of the local axes are used to build the bounding box for vertices attached to the Joint.