Ontario Court: Negligent Parties Liable Under Thin Skull Rule

• The thin skull rule in Canada holds negligent parties fully liable for all harm caused to a plaintiff, even if their pre-existing condition worsens the damage.
• The rule was first confirmed by the Supreme Court of Canada in Athey v Leonati 3 SCR 458.
• The thin skull rule applies when a tort triggers or dramatically worsens a pre-existing condition, making the defendant liable for the full result.
• The crumbling skull doctrine is the counterpart to the thin skull rule and applies when a plaintiff's pre-existing condition was already deteriorating before the accident.

A defendant must take their victim as they find them and is therefore liable even though the plaintiff’s losses are more dramatic than they would be for the average person.

The thin skull rule in Canada has been at the center of personal injury damages assessment for decades. This doctrine holds negligent parties fully liable for all harm caused to a plaintiff, even if their pre-existing condition worsens the damage. The rule was first confirmed by the Supreme Court of Canada in Athey v Leonati 3 SCR 458. In this landmark case, the court ruled that a defendant must take their victim as they find them and is therefore liable for all harm caused, even if it's more severe than what an average person would experience. This principle has been applied consistently in Canadian courts ever since.

The thin skull rule is part of Canadian tort law and is often referred to as the eggshell skull rule or eggshell plaintiff rule. It's essential for lawyers and compliance officers to understand this doctrine, as it holds negligent parties fully liable for all harm caused. The rule doesn't require that a pre-existing condition be visible or diagnosed before an accident; what matters is that it was stable at the time. If a tort triggers or dramatically worsens a pre-existing condition, the defendant is liable for the full result.

The thin skull rule has significant implications for personal injury claims in Canada. Negligent parties must take their victims as they find them, and are responsible for the full result of their negligence. This means that defendants cannot choose who they hurt; if they happen to hurt someone with a pre-existing condition, they are still on the hook for all of it. The rule also has practical implications for lawyers and litigants, as they must carefully assess the plaintiff's pre-existing conditions and determine which rule applies - the thin skull rule or the crumbling skull doctrine.

Lawyers and compliance officers should be aware that the thin skull rule in Canada holds negligent parties fully liable for all harm caused, even if the plaintiff's pre-existing condition worsens the damage. This means that defendants must take their victims as they find them, and are responsible for the full result of their negligence.

Source: Original reporting via Briefly