A legal medical opinion given by a medical expert provides proof for the claimed medical damage for the purpose of claiming compensations at court. In most cases it "replaces" the need for the expert's arrival as a witness to the court of law.

The exception is a medical expert opinion given for damaged caused by a car accident. In this case the court appoints the medical expert and usually his fee is paid by the insurance company being sued.

A legal medical opinion written by a physician who is an expert in his field is based on medical information such as previous medical examinations, imaging tests, physical examination, professional literature, as well as the expert's professional knowledge and experience.

It is very important to provide the expert physician with all the documents and tests related to the case which is brought to court, and not the entire medical history.

There is no legal requirement to present an expert medical opinion when filing a lawsuit demanding compensation for an injury, but without the opinion of a medical expert, the court may rule compensations which do not fit the character and level of injury. In certain cases it is possible to set the medical expert's fee from the body being sued in the complaint filed to the court.