How Does The Thin Skull Rule Apply To Personal Injury Claims


Whether slipping on an icy sidewalk or being hit by a car as you cross the street, you don’t get to choose when or where accidents occur. A similar principle applies to the negligent property owner who did not remove the ice from the sidewalk or to the distracted driver who failed to look out for pedestrians. The party at fault in causing an accident cannot defeat a claim for compensation with a defense based upon a victim’s predisposition to being injured due to a pre-existing condition.

Thin Skull Rule of Personal Injury Law

An old injury or pre-existing medical condition could make someone more likely to suffer an injury in a subsequent accident than would a perfectly healthy person without the condition. For example, the victim of a car accident suffers a fractured forearm. At the trial, the negligent driver who caused the accident offers evidence that a previous injury weakened the bone and made it more susceptible to fracturing. The thin skull rule of personal injury law would prevent the defense from defeating the victim’s claim for compensation.

The thin skull rule stands for the principle that a party at fault in causing an accident and an injury cannot avoid responsibility for paying compensation simply because a pre-existing medical condition makes the victim more susceptible than others to being injured. The thin skull rule precludes a defendant or insurance company from seeking to limit damages by claiming the injuries suffered by the victim are more severe than would have been suffered by a victim without the same pre-existing condition.

Crumbling Skull Rule

The ability of an accident victim to be compensated under the thin skull rule has an important limitation. The crumbling skull rule relies upon the underlying purpose of personal injury law to restore the injured party to the position he or she was in prior to the recent injury. The party at fault in causing an accident is only responsible for additional harm caused to the victim and not for the effects of the pre-existing condition itself.

The distinction between a pre-existing injury subject to the thin skull rule and one under the crumbling skull rule has to do with stability of the existing injury. The thin skull rule is based upon a stable pre-existing condition that would most likely have remained that way were it not for the intervening accident caused by the party being sued for negligence. A pre-existing condition under the crumbling skull rule is one that was not stable before the most recent accident, so the defendant’s conduct accelerated its inevitable deterioration as opposed to causing it.

Evidence to Support a Claim for Compensation

Medical records pertaining to your pre-existing condition are vital to prove the nature of the condition and its stability prior to the most recent injury. The past medical records and the most

recent medical evaluation following an accident that aggravated a prior condition are essential to proving the validity of your claim.

Ontario Personal Injury Lawyers

The personal injury lawyers at Diamond & Diamond have years of experience successfully handling claims for compensation by people suffering injuries in accidents caused by the negligent conduct of other parties. If you suffer an injury and need to file a claim, you should speak to one of our lawyers. Call the Diamond & Diamond 24/7 injury hotline at 1-800-567-HURT or visit our website to speak to someone now. We offer free consultations and case evaluations to injury victims throughout Ontario.