medical jurisprudence or forensic medicine, the application of medical science to legal problems. It is typically involved in cases concerning blood relationship, mental illness, injury, or death resulting from violence. Autopsy (see post-mortem examination) is often used to determine the cause of death, particularly in cases where foul play is suspected. Post-mortem examination can determine not only the immediate agent of death (e.g. gunshot wound, poison), but may also yield important contextual information, such as how long the person has been dead, which can help trace the killing. Forensic medicine has also become increasingly important in cases involving rape. Modern techniques use such specimens as semen, blood, and hair samples of the criminal found in the victim's bodies, which can be compared to the defendant's genetic makeup through a technique known as DNA fingerprinting; this technique may also be used to identify the body of a victim. The establishment of serious mental illness by a licensed psychologist can be used in demonstrating incompetency to stand trial, a technique which may be used in the insanity defense (see insanity), albeit infrequently.

jurisprudence, study of the nature and the origin and development of law. It is variously regarded as a branch of ethics or of sociology. Many of the major systematic philosophers (e.g., Aristotle, St. Thomas Aquinas, and Kant) have expounded jurisprudential theories. Before the 19th cent. most jurisprudents adhered to natural law, which maintained that sound legal doctrine was derivable only from a supposed law of nature established by divine ordinance. The natural-law school did not deny that the details of legal regulation depended upon the will of the sovereign. However, the positivist, or analytical, school, which first became important in the late 18th cent., insisted that law was entirely a matter of sovereign decree, distinct from morality and theology. Among important 19th-century trends was the view, represented by Savigny, that a people's legal system expressed the national spirit. In the mid-19th cent. many jurisprudents attempted to avoid what they felt were theoretical preconceptions and to demonstrate a uniform evolution from primitive times to modern industrialized society. Other thinkers were skeptical of evolutionary explanations and sought the basic principles underlying all systems of law in various fields, including economics and psychology. Among the more important legal thinkers in the United States have been Learned Hand, Oliver Wendell Holmes, and Roscoe Pound.