Legal Definitions - thin-skull rule

The thin-skull rule, also known as the eggshell-skull rule, is a fundamental principle in personal injury law. It states that a defendant must "take their victim as they find them." This means that if a defendant's negligent or wrongful actions cause injury to another person, the defendant is responsible for the full extent of the victim's injuries, even if those injuries are unusually severe due to the victim's pre-existing physical, mental, or emotional vulnerabilities.

In essence, the rule prevents a defendant from arguing that they should not be held fully liable because the victim was unusually fragile or susceptible to greater harm than an "average" person would have been. The defendant cannot claim that the victim's pre-existing condition broke the chain of causation or limited their responsibility for the full scope of the damage.

Here are some examples illustrating the thin-skull rule:

• Example 1: Physical Vulnerability

  Imagine a driver, Mr. Smith, negligently rear-ends Ms. Jones's car at a low speed. For most people, this minor collision would result in a slight jolt and perhaps some temporary whiplash. However, Ms. Jones has a pre-existing, undiagnosed spinal condition that makes her unusually susceptible to injury. As a result of the impact, she suffers a severe herniated disc requiring extensive surgery and long-term rehabilitation.

  How it illustrates the rule: Under the thin-skull rule, Mr. Smith is fully liable for all of Ms. Jones's injuries, including the severe herniated disc and the associated medical costs and pain. He cannot argue that he should only be responsible for the minor whiplash an "average" person would have experienced, because he "takes Ms. Jones as he finds her," with her unique physical vulnerability.

• Example 2: Psychological Vulnerability

  Consider a situation where a landlord, through negligence, allows a dangerous condition to persist in an apartment building, leading to a small fire. While the fire is quickly contained and causes minimal property damage, one tenant, Mr. Chen, who has a pre-existing but dormant anxiety disorder, experiences a severe panic attack during the incident. This event triggers a debilitating resurgence of his anxiety disorder, leading to chronic panic attacks, agoraphobia, and the inability to work for several months.

  How it illustrates the rule: The thin-skull rule dictates that the landlord is responsible for the full extent of Mr. Chen's psychological harm, including the exacerbated anxiety disorder and his lost income. The landlord cannot claim that Mr. Chen's reaction was disproportionate or that an "average" person would not have suffered such severe psychological distress, as they must account for Mr. Chen's pre-existing mental health vulnerability.

• Example 3: Unique Medical Sensitivity

  Suppose a pedestrian, Ms. Davis, is struck by a bicycle courier who negligently swerves onto the sidewalk. The impact causes a relatively minor bruise and scrape on Ms. Davis's leg. However, Ms. Davis has a rare blood clotting disorder that causes even minor injuries to develop into severe, life-threatening hematomas requiring emergency hospitalization and specialized treatment.

  How it illustrates the rule: The bicycle courier is liable for all of Ms. Davis's medical expenses and suffering, including those resulting from the severe hematoma and subsequent treatment. The courier cannot argue that they should only be responsible for a simple bruise, as the thin-skull rule holds them accountable for the full consequences of their actions on Ms. Davis, given her unique medical sensitivity.