The Thin Skulled Plaintiff

Many health care practitioners are familiar with the term “thin skulled plaintiff”. It’s a legal principle that refers to a “vulnerable person”. It’s also an area of personal injury law where medicine and law come together to produce fair results for accident victims that have innate vulnerabilities or pre-existing conditions.

The term “thin skulled plaintiff ” is an odd sounding rule of law. The thin skull rule makes the tortfeasor (an individual who commits a wrongful act that injures another) liable for the victim’s injuries even if the injuries are unexpectedly severe because of a pre-existing condi tion or other vulnerability. There is a general rule in tort law which provides that a tortfeasor “must take his or her victim as they find them”, and is therefore liable even though the victim’s losses are more traumatic than they would be for the average person.

The example often given in legal texts is one where a person (the tortfeasor) negligently bumps into a gentleman and knocks him to the ground. The gentleman bumps his head on the ground. The incident is minor and most people would pick themselves up off the ground and be on their way with perhaps a minor bump to the head. However, the gentleman in this example was born with an “egg shell” type skull and the bump to his head causes a skull fracture and serious brain injury. In this example, it is not a defence for the tortfeasor to say that the gentleman had an unusually thin skull and therefore he should not be held liable for the damages.

Since the thin skulled rule acknowledges that some people are more physically vulnerable than others and the tortfeasor “must take their victim as they find them”, the tortfeasor is therefore liable for the full extent of the injured person’s damages. This rule does not only apply to physical injuries, but the courts have also extended the rule to apply to psychological/psychiatric injuries.

It is not uncommon for personal injury lawyers to invoke the thin skulled rule in order to advance their client’s claims. Cases involving chronic pain for example, are often complex and involve preexisting conditions. Chronic pain cases sometimes involve plaintiffs that have suffered some type of emotional trauma in the past, making them vulnerable to a further trauma such as a motor vehicle crash, even though they may be high functioning members of society. In these cases, the injured person often has an underlying psychological vulnerability.

The thin skulled plaintiff cases are often challenging because most laypeople (i.e. insurance adjusters/jurors) do not readily understand the concept of the “vulnerable person”. Many experts that insurance companies retain will provide med-legal opinions referring to the “average person”, and how “the majority of people” would have recovered from their injuries by now and they should be back to work. These opinions often refer to the fact that there are no “objective signs” of injury identified on radiographic imaging. This type of expert opinion may be appealing to the layperson in cases where the crash and injuries are moderate or relatively minor. However, these opinions often ignore any underlying psychological vulnerability the injured person may have.

Retaining medical or other category experts who understand the concept of the thin skulled plaintiff is the key to success in these cases. We routinely retain experienced psychiatrists and/or psychologists to testify in thin skulled cases so that the jury can readily understand the concept of the vulnerable person, whether we are dealing with a psychological vulnerability or a physical one.

The thin skulled rule is counter-balanced by another legal principle which provides that a tortfeasor does not have to put the plaintiff in a better position than he would have been in if he was never injured. The “crumbling skull” plaintiff (yes, lawyers and judges can be quite morbid) is a relative of the thin skulled plaintiff and it is also a rule of law.

The “crumbling skull” rule simply recognizes that a person’s pre-existing condition was inherent in the person’s “original position” and the tortfeasor need not put the plaintiff in a position better than before the injury occurred. The defendant is liable for the injuries and impairments caused, even if they are extreme, but need not com pensate the plaintiff for any debilitating effects of the pre-existing condition which the plaintiff would have experienced anyway. Many defendants will try to argue that the plaintiff had a “crumbling skull” in cases where the plaintiff is alleging a “thin skull” in order to reduce the damages ultimately payable.

Whether the client is characterized as having a thin skull or a crumbling skull, personal injury lawyers will rely heavily on expert opinions from experienced health care practitioners.

About the Authors


When Rob Durante was called to the bar in 1997, he had been articling for a year with a law firm that specialized in defending insurance companies in personal injury cases. “I developed a sense of wanting to right injustices,” he recalls. “I didn’t want to work for the insurance companies… For me, it’s all about achieving justice for clients, righting wrongs and arranging fair compensation.” Rob joined Oatley Vigmond that same year and has been advocating for seriously injured clients and their families ever since.

To learn more about Rob, please click here.