One advantage that we have when modeling a hand, is that since it is circular in cross-section, we can simply duplicate the segments and connect them in 3D Studio MAX ( 3ds max ).

With the profile selected, go to the Modify Panel in 3D Studio MAX ( 3ds max ) and choose the selection to 'Segment' instead of 'Vertex' in the Line's properties below the Modifier list. Now click and drag around the model / character's profile, using the select tool, so that all the segments in the profile gets selected. Now hold down the 'Shift' key and drag the segment along the 'Y' axis in the perspective view in 3D Studio MAX ( 3ds max ). This will create a duplicate segment inside within same profile line of the model / character.

Connect the corresponding vertices in each segment starting from the shoulder one to the wrist using the 'Create Line' tool as shown in the figure. Also create a refernce model / character to see the shape of the arm in a 3d shape in 3D Studio MAX ( 3ds max ).