Legal Definitions - eggshell skull rule

The eggshell skull rule (also known as the thin skull rule) is a legal principle that holds a person who causes harm fully responsible for all the injuries that result, even if the victim had a pre-existing vulnerability that made their injuries much worse than an average person would have experienced. In essence, the law states that a wrongdoer "takes their victim as they find them," meaning they cannot argue that they should pay less compensation simply because the victim was unusually susceptible to injury.

This rule applies when a defendant'snegligent or intentional actions directly cause an injury, and that injury is then magnified due to the plaintiff's unique physical or psychological characteristics. It's crucial to understand that the rule does not make the defendant liable for unrelated pre-existing conditions, only for the extent to which their actions exacerbated or triggered a more severe outcome because of those conditions.

Here are some examples to illustrate the eggshell skull rule:

• Example 1: Severe Allergic Reaction

  Imagine a restaurant employee negligently serves a dish containing peanuts to a customer who explicitly stated they have a severe peanut allergy. While an average person might enjoy the dish without issue, the allergic customer suffers a life-threatening anaphylactic shock, requiring immediate hospitalization and extensive medical treatment. Under the eggshell skull rule, the restaurant would be liable for all the medical costs and suffering related to the severe allergic reaction, even though the employee's negligence would have caused no harm, or only minor discomfort, to most other patrons. The restaurant "takes the customer as they find them," including their unique and severe allergy.

• Example 2: Exacerbated Mental Health Condition

  Consider a pedestrian who is struck by a car due to a driver's negligence. The pedestrian sustains minor physical injuries, such as bruises and a sprained ankle. However, unknown to the driver, the pedestrian had a pre-existing, dormant psychological condition (e.g., Post-Traumatic Stress Disorder from a past unrelated trauma). The stress and shock of the accident trigger a severe and debilitating relapse of their PTSD, leading to long-term therapy, inability to work, and significant emotional distress. The eggshell skull rule dictates that the negligent driver is responsible for the full extent of the pedestrian's psychological harm, including the severe exacerbation of their pre-existing condition, even though an average person might only have experienced temporary emotional upset from such an accident.

• Example 3: Brittle Bone Disorder

  Suppose a person with a rare and undiagnosed brittle bone disorder (osteogenesis imperfecta) is involved in a minor fender-bender caused by another driver's carelessness. While the collision is slight and would typically result in no more than a minor bump or bruise for most individuals, the person with the disorder suffers multiple severe fractures throughout their body. The eggshell skull rule ensures that the negligent driver is held accountable for all the extensive injuries and medical expenses incurred by the victim, despite the fact that the severity of the fractures was entirely due to the victim's unique and fragile bone condition, which the driver could not have known about.