Scans of the ice worms bones show that they have a surprising degree of flexion in them. This likely allows the bones to compress inward when the ice worm is burrowing. A total rigidity in the bone structure might result in deformation of the skeletal structure over time. There is evidence of muscle insertions that would manipulate the compression or decompression of the ice worm’s long rib cage.
These ice worm bones appear relatively intact; it seems that other large land predators in the region tend to leave the worm carcass alone after death.