 Inasmuch as the "common knowledge" exception to the foregoing rule does not apply on the facts here alleged, the trial court could not properly conclude as a matter of law that defendants' standard of professional care did not include the diagnostic and treatment procedures outlined in the complaint.Plaintiff is therefore entitled to the opportunity to prove by way of expert testimony that in the circumstances of this case a reasonably prudent physician would have followed those procedures.Whether the physician would have followed the procedure of reporting plaintiff's injuries to the authorities, however, is not solely a question of good medical practice.