The muscles, organs and skin are liquefied, with the cadaver's bones, cartilage and hair remaining at the end of this process.
Although an exposed human body in optimum conditions can be reduced to bone in 10 days, a body that is buried 1.2 m under the ground retains most of its tissue for a year.
The five stages of decomposition—fresh (aka autolysis), bloat, active decay, advanced decay, and dry/skeletonized—have specific characteristics that are used to identify which stage the remains are in.
Livor, rigor, and algor mortis
Goff explains, “[T]he blood begins to settle, by gravity, to the lowest portions of the body,” causing the skin to become discolored. This process may begin after about an hour following death and can continue to develop until the 9–12 hour mark postmortem.
During the first few months underground, the body will typically undergo active decay, putrefaction, and blackening. Over several decades, the tissue and organs will continue to break down and liquefy until only the teeth remain. Of course, many variables can affect this process.
After two weeks, the body starts to bloat and change its color to red after the blood present in the body starts to decompose. Once the corpse surpasses the fourth week, you can witness liquefaction in the rest of the remains. The teeth and nails also begin to fall during this time frame.
However, on average, a body buried within a typical coffin usually starts to break down within a year, but takes up to a decade to fully decompose, leaving only the skeleton, Daniel Wescott, director of the Forensic Anthropology Center at Texas State University, told Live Science.
Decompensation progresses over a period of minutes even after the pulse is lost. Even when vascular collapse is the primary event, brain and lung functions stops next. The heart is the last organ to fail.
Within hours, blood is pulled downwards, causing splotches on the skin. Because the heart is no longer pumping blood around the body, it starts being pulled down by gravity. As the blood pools, patches appear on the skin within 30 minutes of death.
After a few weeks, nails and teeth will fall out. After 1 month, the liquefaction process commences. During this stage the body loses the most mass. The muscles, organs and skin are liquefied, with the cadaver's bones, cartilage and hair remaining at the end of this process.
Do they remove organs when you are embalmed? One of the most common questions people have about embalming is whether or not organs are removed. The answer is no; all of the organs remain in the body during the embalming process.
3-5 days after death — the body starts to bloat and blood-containing foam leaks from the mouth and nose. 8-10 days after death — the body turns from green to red as the blood decomposes and the organs in the abdomen accumulate gas. Several weeks after death — nails and teeth fall out.
Preserving the Deceased's Remains
To prevent rapid decay, funeral homes drain out the blood and other fluids since they facilitate faster decomposition. They then replace it with anti-decay chemicals.
By three days, internal organs have decomposed. From three to five days after death, the body will begin to bloat from gasses produced from internal decomposition. The body could actually double in size and turn a greenish color. Extremely unpleasant and long-lasting odors called putrification begins.
Caskets made from either metal or wood will take an average of 50 or more years to decompose underground. The casket's duration depends on the type of wood used to build it and the composition of chemicals found on the grave.
For the most part, however, if a non-embalmed body was viewed one year after burial, it would already be significantly decomposed, the soft tissues gone, and only the bones and some other body parts remaining.
For the first few minutes of the postmortem period, brain cells may survive. The heart can keep beating without its blood supply. A healthy liver continues breaking down alcohol. And if a technician strikes your thigh above the kneecap, your leg likely kicks, just as it did at your last reflex test with a physician.
A conscious dying person can know if they are on the verge of dying. Some feel immense pain for hours before dying, while others die in seconds. This awareness of approaching death is most pronounced in people with terminal conditions such as cancer.
The brain lives on for 30 seconds after death.
8. The body as a whole may be dead, but certain parts within are still alive. The brain is the first organ to begin to break down, and other organs follow suit. Living bacteria in the body, particularly in the bowels, play a major role in this decomposition process, or putrefaction.
Between a half hour to three hours after death, the eyelid loses its elasticity, the pupil dilates and there is a distinct change in the cornea, which is normally transparent.
While the rest of our body shrinks as we get older, our noses, earlobes and ear muscles keep getting bigger. That's because they're made mostly of cartilage cells, which divide more as we age.
Generally speaking, a body takes 10 or 15 years to decompose to a skeleton. Some of the old Victorian graves hold families of up to eight people. As those coffins decompose, the remains will gradually sink to the bottom of the grave and merge.
After 5 years of burial, the body's condition may be unrecognizable. Most of the tissues will have decomposed to the point where there is very little – if any – soft tissue left. The body's skeletal remains will be exposed, and there may be some hair and nails that have survived.