A corpse, also known as a cadaver, is the body of a deceased organism, most commonly referring to human remains. It represents the physical form after all life functions have ceased. The study of corpses provides significant information across various biological fields, including forensic science, anatomy, and ecology.
Recognizing Death
Determining when a living body becomes a corpse involves specific medical and biological criteria. Death is defined as the irreversible cessation of vital functions, including the permanent loss of circulatory and respiratory functions, as well as the irreversible cessation of all brain activity, including the brainstem. Signs indicating death include the absence of a pulse, no breathing, and a flat electrocardiogram. Brain death, characterized by the complete and irreversible loss of all brain functions, is legally and medically recognized as death. These criteria establish the point at which the complex biological systems of the body shut down permanently.
The Body’s Immediate Changes After Death
Following death, the human body undergoes a series of predictable physical and chemical changes. These early post-mortem indicators provide insights into the time and circumstances surrounding death.
One of the first noticeable changes is Algor Mortis, the cooling of the body. After death, the body loses its ability to regulate temperature and gradually cools or warms to match the ambient environment. The body typically loses approximately 1.5 degrees Fahrenheit per hour, though the rate can be influenced by environmental temperature, clothing, and body composition.
Concurrently, Livor Mortis, or post-mortem lividity, develops as blood settles in the lower parts of the body due to gravity. With circulation ceased, red blood cells sink, causing a purplish-red discoloration in dependent skin areas. This pooling becomes apparent within 30 minutes to two hours after death and typically becomes “fixed” after eight to twelve hours, meaning the discoloration will not shift if the body’s position is changed.
Rigor Mortis, the stiffening of muscles, is another significant post-mortem change. This occurs because the body’s cells cease aerobic respiration, leading to a depletion of adenosine triphosphate (ATP). Without ATP, muscles remain contracted, causing rigidity. Rigor mortis usually begins two to six hours after death, starting in smaller muscles, and typically dissipates within 36 hours as decomposition progresses.
What Influences Decomposition
Beyond these immediate post-mortem changes, various factors affect a corpse’s decomposition rate. Environmental conditions play a significant role. Temperature is a primary driver, with warmer temperatures accelerating decomposition due to increased microbial and insect activity, while colder temperatures slow or even halt the process.
Moisture levels also impact decomposition; damp conditions generally promote faster decay. However, extremely wet or dry conditions can slow decomposition, with very dry environments sometimes leading to mummification. The presence of insects and scavengers significantly accelerates decomposition, as they consume tissues and introduce bacteria. Intrinsic factors, such as the individual’s health at the time of death and clothing worn, also influence the rate of decomposition.