Reduction of the Rib Cage.
The posterior portion of the chest may be of such a diameter that is too large to extract. In such cases, one channel of the fetatome is unthreaded and the free end of the wire is passed through the chest cavity and the diaphragm with the aid of an introducer. The wire is then directed along the exterior wall of the chest and re-threaded through the open channel of the fetatome. The wall of the chest is then cut longitudinally. This allows collapse of the chest walls which reduces the diameter of the chest.
Bierschwal CJ and deBois CHW (1975)