Eggshell Skull Rule

The eggshell skull rule, also called the thin skull rule, is a principle of common law tort systems holding that a defendant is fully liable for the harm actually caused to a victim even if the unusual physical frailty or pre-existing condition of the victim made the resulting injury far worse than it would have been for an ordinary person. The rule applies across negligence, intentional torts, and strict liability, and courts have extended its logic beyond physical vulnerability to psychological, social, and even economic characteristics of a victim that increase the severity of an injury. Its rationale is that a wrongdoer should not escape responsibility for the actual harm caused merely because the extent of that harm was not foreseeable, since the wrongdoer takes the victim as found. The main limitation of the rule involves intervening causes: an independent later event, such as negligent medical treatment, can break the chain of causation and limit the liability of the original defendant for everything that follows.