Okla. Stat. tit. 76, § 76-21: Presumption of negligence

In any action arising from negligence in the rendering of

medical care, a presumption of negligence shall arise if the

following foundation facts are first established:

1. The plaintiff sustained any injury;

2. Said injury was proximately caused by an instrumentality

solely within the control of the defendant or defendants; and

3. Such injury does not ordinarily occur under the

circumstances absent negligence on the part of the defendant.

If any such fact, in the discretion of the court, requires a

degree of knowledge or skill not possessed by the average person,

then in that event such fact must be established by expert

testimony.