Postmortem Changes and Estimation of Time of Death

A set of vocabulary flashcards based on postmortem changes, stages of death, and methods for estimating the time of death.

Uniform Determination of Death Act (UDDA)

A legal standard adopted by the American Bar Association and American Medical Association stating that an individual is dead if they have sustained irreversible cessation of circulatory and respiratory functions, or irreversible cessation of all functions of the entire brain, including the brain stem.

Postmortem Interval (PMI)

The duration of time between death and the attempt to determine the time of death or time since death.

Pallor Mortis

The postmortem paleness in the face and other body parts caused by the cessation of blood circulation, typically showing its first signs within $15\text{--}30\text{ minutes}$ of death.

Algor Mortis

The postmortem cooling of the body from an average temperature of $37^\text{o}\text{C}$ due to cessation of metabolic activity and thermoregulation, occurring at an average rate of approximately $1.5^\text{o}\text{F/hour}$.

Rigor Mortis

The postmortem stiffening of body muscles caused by the depletion of adenosine triphosphate ($\text{ATP}$).

Nysten's Law

A rule governing the sequential pattern of rigor mortis, which affects first the muscles of mastication, followed by the face and neck, upper trunk and arms, and lastly the legs and feet.

Livor Mortis

The purplish-blue discoloration of the skin in dependent parts of the body caused by gravitational pooling of blood after cardiac arrest.

Somatic Death

An immediate postmortem change defined by the irreversible cessation of the vital functions of the brain, heart, and lungs.

Molecular Death

An early postmortem phase, also known as cellular death, during which tissues gradually die and show physical changes, though muscle tissue temporarily responds to electrical stimuli before primary flaccidity.

Tache Noir de la Sclerotique

A dark, reddish-brown or black triangular discoloration formed on the exposed sclera when the eyes remain open after death.

Kevorkian Sign

The postmortem fragmentation or "trucking" of blood vessels in the retina, appearing within a few minutes after death and lasting for about an hour.

Thanatometer

A $25\text{ cm}$ long thermometer with a range from $0^\text{o}\text{C}$ to $50^\text{o}\text{C}$ used to record postmortem core body temperature.

Henßge Nomogram

A standard chart method used in forensic pathology to estimate time since death based on rectal temperature, ambient temperature, and body mass.

Autolysis

The postmortem self-digestion and breakdown of body cells and tissues brought about by intrinsic enzymes without bacterial action.

Maceration

The autolytic fermentation of an unborn fetus inside the amniotic cavity, characterized by skin slippage and blackish-brownish tissue discoloration.

Putrefaction

The decomposition of organic body tissues carried out by microbial and bacterial action, starting within an hour of death and reaching peak activity around $24\text{ hours}$.

Marbling

The dark, tree-like vascular pattern outlining superficial blood vessels on the skin during putrefaction, caused by bacterial hydrogen sulfide reacting with hemoglobin inside decaying erythrocytes.

Postmortem Purging

The expulsion of dark putrefactive liquids and gases from the mouth and nostrils due to increased intra-abdominal pressure generated by bacterial activity.

Casper's Dictum

A forensic rule stating that a body decomposes in air twice as rapidly as submerged in water, and eight times as rapidly as buried in earth.

Adipocere Formation

A postmortem modification of putrefaction involving hydrolysis and hydrogenation of fatty tissues into a yellowish, greasy, waxy substance composed primarily of palmitic, oleic, and stearic fatty acids.

Mummification

A modification of putrefaction occurring in hot, dry, arid environments, characterized by severe desiccation and dehydration that leaves dark, leathery, shrunken skin over bony prominences.

Vitreous Potassium Estimation

A biochemical method of determining postmortem interval based on measuring the postmortem rise of potassium levels in the vitreous humor.