Otoliths are the bones least likely to be broken by physical trauma in vertebrates. While some animals have similarly sized bones elsewhere in their bodies, these tend to in the extremeties (feet and knuckles in particular) and more exposed to trauma than the otoliths, which are protected by the skull.

The next time someone threatens to break every bone in your body, it may or may not be comforting to realise that they probably don't include your otoliths in this threat.