“Human Decomposition�

The subject of “traumatic injuries� appears to be a crowd favorite whenever I give a presentation on death investigation. Images of gunshot wounds, blunt force trauma, and impact injuries coupled with methods for evaluating external trauma always makes for a captive audience. Still, I find that I enjoy discussing human decomposition more than trauma.

Rigor mortis, livor mortis, and algor mortis are relatively short-lived, but they are admittedly more helpful to an investigator when determining postmortem interval than the various stages of decomposition. Conversely, the process of decomposition is much longer, but by comparison is a very weak indicator of actual time of death because the stages are so easily influenced by the individual’s characteristics—primarily age, size, and health—and environmental variables.

A good example of environmental variables is to consider how a steak would be affected by its environment. A steak located outside will go bad much faster than a steak that is in an air conditioned kitchen. Insect activity is much more likely outside, and there is also exposure to circulation of air and sunlight while outdoors. A steak sitting on the kitchen counter will go bad much faster than a steak in the freezer. Even the steak in the freezer will go bad despite the attempt at preservation. Similarly, a body in a morgue cooler will still decompose, just at a much slower rate.

Decomposition is certainly one of the more repulsing aspects of death investigation but just as equally one of the more natural (when compared to homicides and auto fatalities). The stages of postmortem decomposition generally follow the same process. From the moment that a person dies, the body begins to break down chemically just as any other carbon-based substance does. Micro-organisms work on the inside of the body while insects—and sometimes animals—work on the outside of the body.

On average, external signs of decomposition begin to appear about 24 hours after death. The soft, moist tissue inside the body begins to break down faster than the more durable exterior surfaces of the skin. Consequently, escaping gases from inside the body often create a uniquely repulsive odor even before any external signs of decomposition are present. Moving the body to examine it or to remove it from a scene only increases the amount of the gas and smell. The best way to approximate the smell is to leave a sealed gallon of milk with a little milk in the bottom in direct sunlight. After two weeks have passed, remove the lid and insert nose.

As the smell becomes stronger, large areas of skin will begin to show signs of a blueish-green discoloration. This color usually starts to become visible around the abdominal region. This skin discoloration is usually accompanied by a “marbling� of the skin that is deep purple in color. As blood vessels and superficial veins begin to break down, the blood diffuses into the soft tissue and looks similar to the vein pattern in a slab of marble.

After death, the digestive enzymes that were previously tasked with breaking down food particles become stagnant and begin to break down the lining of the gastrointestinal tract. The resulting gases from these chemical processes will eventually cause the body to bloat at about 36 hours after death. The abdomen becomes distended and areas of soft tissue around the genitalia and the eyelids will have a “swollen� appearance. This swelling around the eyes is often mistaken as a sign of trauma by first responders.

A few days after death, signs of skin slippage will begin to appear. Outer layers of skin at the feet and hands will separate from underlying layers, which looks similar to a loose fitting rubber glove. Fingernails can easily be removed and areas of skin that appear to be intact may slide off when the body is handled for examination or movement. Sections of hair may also pull free if the follicles are adhered to another surface like carpet or bedding.

Despite the inaccuracy of decomposition when trying to determine time of death, I find it to be the most interesting of all the postmortem changes because the process is the most complex. The variables that are involved make it a challenge to interpret its significance. Whereas rigor, livor, and algor mortis have more solidified rules as to their application, the uniqueness of decomposition requires an investigator rely on their own past exposures to decomposed bodies to make an educated estimate at postmortem interval.

17 Responses to “”

  1. June 2, 2005 at 11:18 am

    Two questions:

    1. Can you explain the differences between rigor, livor, and algor mortis?

    2. Do you know much about the rise of vampire-type fables in Easern Europe? I know only a little – essentially, the signs of the recent dead (blood in mouth, lack of colour in face, occasional groans from escaping gasses) prompted tales to be told. I read somewhere that arms straighted out due to rigor (?) mortis would protude above shallow graves, giving more evidence to the idea of the undead. Not sure if you can or want to comment or expand, but your perspective on this issue would be … unique.


    I’d be glad to. It’s been a busy week, but I’ll have a response up this weekend. Please stay tuned…


  2. June 2, 2005 at 11:36 am

    I used to work at a summer camp where, when someone said something in casual conversation that was exceedingly funny, we would record that quote in magic marker on the rafter of the cabin.

    “Still, I find that I enjoy discussing human decomposition more than trauma.”

    This one would definitely end up on the rafters.

  3. 3 Heidi
    June 2, 2005 at 12:42 pm

    Actually I understand what you mean. While there’s always the ‘rubbernecking’ factor in seeing a gory trauma, there’s a lot more interest for me in the postmortem processes. Suppose that’s due to my high exposure to such, growing up in a medical family and/or life in the country, but even as an older kid I’d find myself studying the photos in the newsmagazines, trying to estimate how long they’d been dead from just what I could see. (morbid kid? me??). I’ve decided that if I never do anything else in the field, I can at least will my body to UTenn so I can contribute a little to the furtherance of research.

  4. 4 Paolo
    June 2, 2005 at 5:46 pm

    I laugh at what Douglas just wrote.

    Interesting you brought that up about environment being a factor in decomposition, as it is a major factor in warmer states like here in Florida. We had a woman who’d left her windows open before she died, and removing her from her house was like trying to handle a slippery fish.

    Nice usage of the termonology by the way!

  5. 5 Jim
    June 4, 2005 at 9:41 am

    Your mention of insects reminded me of a job I did a couple of years ago. I was hired to paint an apartment where a man had commited suicide. He had shot himself in the head, and managed to shoot a few walls somehow as well. The apartment had been cleaned by a crime scene cleaner, but they didn’t get everything. High up on the walls were small specks of blood, the blinds on the window had “debris” inside the track, and the sub-floor (carpet had been removed) had a, let’s say odd color, stain on it. Fun stuff. What got me were the window tracks. Every one of them were full of dead flies. I can only imagine what the body must have looked like.

  6. 6 Di
    June 5, 2005 at 8:06 pm

    As always, fasinating stuff!

  7. June 6, 2005 at 9:14 am

    Thanks for describing what happens. The only time I’m ever around someone who would be able to answer the question is at a funeral home for a wake — hardly the most appropriate time.

  8. June 17, 2005 at 5:39 pm

    I think I’m going to puke…

  9. October 31, 2005 at 3:59 pm

    What are the gases released & what are the dangers associated with the gases to the clean up personnel involving decomposition?


    “The putrefaction gases include methane, carbon dioxide, hydrogen and particularly malodorous ammonia, hydrogen sulfide and mercaptans” (quoted from page 32 of Spitz and Fisher’s Medicolegal Investigation of Death, 3rd ed.)

    Other than smell and risk of vomiting, I’m not aware of any short-term dangers resulting from exposure to these gases. I can only hope that there aren’t any long-term ones either. Most of the risk associated with any bi-product of decomposition are the same same as those pertaining to bloodborne pathogens. My personal practice is to use the same precautions I would when handling someone else blood.

    I hope that answers your question. Sorry for being so vague. I’m reluctant to offer any specifics on the subject. With my luck, someone wouldn’t research the subject beyond what I wrote, and I’d end up getting sued.

    A Douglas

  10. 10 Shannon
    November 23, 2005 at 11:57 pm

    Recently, a man died in the apartment above mine. He was dead for several days – at first we thought his refrigerator died, and contacted our landlord. But, the next day, when blood and bodily fluids started dripping from our bathroom and kitchen ceiling – we telephoned the police.

    A Hazmat team is currently working on removing the contaminated bits of the house, while we stay in a hotel.

    Once they are finished, how concerned should we be that that awful smell will return – say, when the heat is cranked, or on a hot summer day?

    I’ll answer this comment in my next post…

  11. 11 Rose N. Roussell
    February 11, 2006 at 10:01 pm

    I have a question? What effect does the odor of a decomposed human body have on a person who lives in the room after the body has been removed.
    My husband check into a hotel room in New Orleans where a sick woman died. He was not told that this have happened in this room until a week later. But he complained about the bad smell in the room to the front desk. He bougth differnt spray to kill the smell,but nothing worked. After a week he was feeling sick with headackes and complined of breathing problems. Finly he was places in another room. That is when someone with the cleaning crew told him that a person had died in the room he was in and the body was not found for nine days. We know the they did not clean the room properly because this hotel was filled with fema evacuees. What sould we do?


    Check out my post “Room to Breath� for my thoughts on ill health effects.

    A Douglas

  12. 12 lindsey
    March 16, 2006 at 4:39 pm

    i want to be a morticion. I think this sounds like fun though 🙂

  13. 13 Khadeidra
    June 11, 2006 at 7:16 pm

    the smell of a decomposed body is the worst smell I have ever incountered

  14. August 18, 2006 at 7:07 pm

    you present an easily understood,detailed explanation of human decompositon,is fascinating,and i thank you .elizabeth.

  15. 15 Heather
    September 23, 2006 at 10:40 am

    My mother found her partner in bed and had been there for about 8 days. I wanted to get a sense of how she last saw him and gain perspective on some of her trauma. Thank you.

  16. 16 Crystal T.
    March 13, 2007 at 1:19 pm

    What would “4 + rigor mortis and 4 + posterior livor mortis are present” mean to you?


    No idea about the “4 +”. I can only assume someone is using a numbering or coding system to describe the degree of rigor and livor. For livor, we note the region (anterior, posterior, face, etc.) and whether it is absent, fixed, or blanching. For rigor, we note the location (legs, arms, jaw, neck, etc.) and whether it is soft, rigid, passing, passed, etc. Sorry I couldn’t be more help.

    A Douglas

  17. 17 Crystal T.
    March 28, 2007 at 12:44 pm

    That’s O.K. Thanks for your time.

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