Fortunately, the law recognizes that plaintiffs face certain difficulties in proving medical negligence. If a patient injured as the result of a medical procedure does not know exactly what caused his or her injury, but it is the type of injury that would not have occurred without negligence on the part of his or her health care provider(s), he or she may invoke a legal doctrine known as "res ipsa loquitur." Translated, this Latin phrase means "the thing speaks for itself," and implies that the plaintiff need only show that a particular result occurred and would not have occurred but for someone's negligence.

Once this doctrine is successfully invoked, the burden is not on the plaintiff to show how the defendant was negligent, but on the defendant to show that he or she was not negligent. To invoke this doctrine successfully, a plaintiff has to show that:

1) Evidence of the actual cause of the injury is not obtainable;

2) The injury is not the kind that ordinarily occurs in the absence of negligence by someone;

3) The plaintiff was not responsible for his or her own injury;

4) The defendant, or its employees or agents, had exclusive control of the instrumentality that caused the injury; and

5) The injury could not have been caused by any instrumentality other than that over which the defendant had control.