What is the standard of care, knowledge and care prevailing in the medical community?

In Folk v. Kilk (1975) 53 Cal.App.3d 176, 185, 126 Cal.Rptr. 172, 178, the court stated that, 'The law requires only that doctors exercise that reasonable degree of skill, knowledge and care ordinarily possessed and [71 Cal.App.3d 494] exercised by doctors under similar circumstances in diagnosis and treatment, with no different or higher degree of responsibility than that obtaining in their professional community.' As such, the court went on to say that, 'The standard of skill, knowledge and care prevailing in a medical community is ordinarily a matter within the knowledge of experts. Where a medical process or procedure is not a matter of common knowledge, expert testimony is necessary to determine whether a probability of negligence appears from the happening of an accident or untoward result.'