the first thing i had to do is set up the fracture. I did this by creating vornoi fracture
I then convert my arm geometry (in its default pose) to a volume using an iso offset. I also mixed that arm volume with a volume from a box of similar proportions to my arm geo. I plug that volume into a volume vop giving me ramp based on the BBOX positions and the position attributes, this gives me more control over the where I want the volumes to be within that arm shape. I then plug that data into a vopsop connecting the position into a volume sample file(saved out geo from a file node).
From here I scatter points and plug hook those points into my vornoi fracture sop.