- The injury would not ordinarily have occurred without someone's negligence.
- The instrumentality which caused the injury was under the exclusive control of the defendant during the time of the likely negligent act.
- The plaintiff's voluntary or involuntary actions did not contribute to the injury.
- A patient came in walking to the out-patient clinic for injection. After injection was administered to his buttocks, the patient experienced extreme pain, leg weakness, and was subsequently paralyzed.
- The presence of sponges in the patient's abdomen after an operation.
- Fracture on a newly-delivered baby born by breech presentation.
Furthermore, it is important to note that res ipsa loquitur is not synonymous with prima facie, another legal exression. Prima facie is a term which means "the matter seems obvious and self-explanatory". Res ipsa loquitur, on the other hand, is the legal argument which means "that because it is so obvious, the plaintiff need not explain further to prove the defendant's liability". For example:
There is a prima facie case that the defendant is liable. The patient consented to an appendectomy and the surgeon removed the patient's appendix. After a week, the patient sought medical consultation due to severe stomach pains. Serial radiologic studies reveal that sponges were left inside the patient's abdomen. Res ispsa loquitur.
Indeed, it requires no further explanation to establish that a surgeon who performs appendectomy and leaves sponges inside a patient's abdomen after the operation is negligent as there is no legitimate reason for him to do so.