Determining whether a young child's injuries are due to physical abuse is often extremely difficult. Frequently, the child is nonverbal, and there are no witnesses other than the caretakers that are suspected of abuse. Expert medical opinion is often necessary to diagnose abuse. However, the process by which physicians diagnose physical abuse is something of a mystery to many attorneys, even to those who routinely handle such cases. The medical literature is often impenetrable to those without special training, leading attorneys to defer to expert opinion without fully understanding the basis for such opinion. This is unfortunate. Without understanding the research that underlies expert medical judgment, an attorney can neither make full use of the physician's expertise, nor adequately cross-examine an opposing expert.