Rigging Characters - Beginning Game Art in 3ds Max 8 - page 290

7. Because of the position of the thumb, there is no exact way to place the bones.
In this example, I placed the bones in the Side view, as shown in Figure 7.72.
Figure 7.72 Build the joints for the thumb from the Side view.
8. Move the joints of the thumb up in the Front view, as shown in Figure 7.73.
Figure 7.73 Move the joints of the thumb up in the Front view.