Eggshell-Skull Rule Law and Legal Definition

Eggshell skull rule is a principle of trots law that a defendant is liable for a plaintiff's unforeseeable and uncommon reactions to the defendant's negligent or intentional act. The "eggshell skull" rule makes the tortfeasor take his/her victim as s/he finds him.

If a tortfeasor inflicts a graver loss on his victim than one would have expected because the victim had some pre-existing vulnerability, that is the tortfeasor's bad luck; you take your victim as you find him. That is the famous "eggshell skull" rule of tort law. [Schmude v. Tricam Indus., 556 F.3d 624, 628 (7th Cir. Wis. 2009)]

In calculating damages in an eggshell skull case the trier of fact must make an adjustment for the possibility that the preexisting condition would have resulted in harm to the plaintiff even if there had been no tort. The tortfeasor may be excused from liability where the claim of damages is so remote and so out of proportion to the culpability of the tortfeasor that, as a matter of public policy, the trial court concludes that the defendants are not to be held liable for this element of damages. [Stoleson v. United States, 708 F.2d 1217 (7th Cir. Wis. 1983)]

Eggshell skull rule is also known as eggshell-plaintiff rule; thin-skull rule; special-sensitivity rule or old-soldier's rule.