What is Livor Mortis?
When a person dies and the heart stops pumping, blood pools and settles in the lower regions of the body. This is a result of gravity, causing the effect known as Livor Mortis. This settling process is more commonly referred to as lividity and begins to occur about two hours post death. As the body decomposes blood seeps through the tissues turning the appearance of the skin purple. The skin will lack coloring if pressed against an object. After approximately eight hours lividity remains set even if the skin is pressed.
Lividity is an early visible sign of death
So why is any of this important to know? First off, lividity is one of the first visible signs of death and helps investigators determine the position of the body shortly after death. It assists investigators in determining if the body has been moved after death. It is a clear indicator to whether the death occurred at the current location or some other place. Lividity patterns should match the body’s positioning or an investigator will know something is amiss at this crime scene. Environmental conditions can affect lividity. The higher the temperature, the faster the rate of lividity. Heat increases and cold slows the rate of decomposition.
The decomposition process
The decomposition process is caused by bacteria and other microorganisms breaking down the bodies structures. While not absolutely precise due to environmental changes, decomposition can further assist investigators in determining a window of time when the death most likely occurred. Initially, the body appears normal from the exterior, even though the decomposition process has begun immediately upon death. As time passes changes occur as a result of decomposition. Around day three the skin usually appears marbled and the face becomes discolored.
Using food to determine time of death
Stomach and intestinal contents also help in determining general times of death. If there is undigested food in the stomach, forensic pathologists can determine the type of food consumed. This indicates death occurred within two hours of the meal. If the stomach lacks food, but the small intestine contains food the death occurred within six hours of the last food intake. Finally, if the small intestine is void of food but wastes are noted in the large intestine death most likely occurred twelve hours or more after the last ingestion of food.
Around the 5th day, the body begins to bloat and odor can be detected. This stage is commonly referred to as initial putrefaction. As the decay enters into the advanced stages of putrefaction, the odor becomes extremely rank due to gases building up in the body causing bloating where it eventually ruptures the body cavity allowing the built-up gases to escape. This usually occurs around ten days to two weeks post-death, depending on environmental conditions.
Next week we will look at Algor Mortis and Rigor Mortis leading to Entomology and tie everything together in order to gain a greater understanding of what is involved in estimating the time of death.