Rapid vs Gentle bone removal

The mastoid bone is surrounded by structures that must be left intact but there is scope in a dissection for both rapid bone removal and gentle polishing action. The cortical bone of the surface of the mastoid bone may be removed aggressively when the dissection is well forwards of the sigmoid sinus. Parts of the cellular pneumatised bone may be removed aggressively when the cortical bone has been removed enough to establish the area of the pneumatised bone.