Adamantium Skeleton

Adamantium Skeleton is a Fallout 3 Perk.

With the Adamantium Skeleton perk, your limbs only receive 50% of the damage they normally would.

Trivia
May be a reference to Marvel Comics superhero Wolverine's modified skeleton. This also may be a reference to adamantium armor found in The Elder Scrolls III: Morrowind GOTY since both Fallout 3 and The Elder Scrolls series are made by Bethesda?