Armature Follows Path

I have an armature, trying to animate it. I want to limit it’s “range of motion” to a path (spline/curve). Does anyone know how to do this?
http://i45.tinypic.com/2qc1rnc.jpg

Not sure what you mean by limit range of motion, but if you just want the bone to follow the path add a follow path constraint on the bone in pose mode.

http://wiki.blender.org/index.php/Doc:Manual/Constraints/Follow_Path

Randy