The Stages of Death

Most people think of death as an either-or proposition: you’re either dead or alive. I’m not here to dispute that (sorry, zombies!). Instead, I want to talk about what a body goes through immediately after death. These are known as the stages of death or post-mortem changes.

If you’re a mystery writer, you’ve probably written about a medical examiner or detective estimating the time of death based on some or all of these stages. Even if you haven’t, most people have heard the term ‘rigor mortis.’ In fact, that (and a few others) are the go-to ways for investigators to predict when the person died during the early post-mortem interval (up to 72 hours after death).

But crime writers aren’t the only people who need to know their stuff. Even fantasy, horror, and sci-fi should start with how things work in reality and then purposefully change it up. You have to know the rules to break them.  

Pallor Mortis
Pallor mortis (paling skin) happens more quickly than any of the other stages, although it is mostly noticeable in people with lighter skin tones. It generally occurs within 15-30 minutes after death. This is mainly used to see if the body is exceptionally fresh, i.e., if the person died within the past half hour.

Corneal Opacity
One of the first things a casual observer would notice in a corpse is corneal opacity, sometimes called clouding. This is when the eyes become cloudy and have a distinct appearance. Corneal opacity typically happens within two hours of death.

Livor Mortis
Livor mortis refers to skin discoloration and is the cousin of pallor mortis since they’re both caused by the same thing: gravity. Blood vessels are weighed down in whatever position the body is in, so an observer will notice blue/purple discoloration from blood pooling in whichever parts of the body are closest to the ground.

Notice I said closest, not touching the ground. That’s because the weight of the body actually stops blood from pooling in the skin that’s making contact with the ground. A seated corpse, for example, would have blood pooling in the lower thighs, outer flanks, backs of knees, and ankles, while the heels and the majority of the buttocks, upper thighs, and calves would be weight-bearing and therefore sans blood.

Algor Mortis
This is a fancy way of saying that a body cools off after death. Surrounding temperatures and the body’s condition can seriously affect this. A body typically cools 1.5 degrees Fahrenheit per hour (only perceptible to human touch after a few hours at least). Although this is one of the most accurate ways to measure the post-mortem interval, it requires taking the body’s temperature with a rectal thermometer. Unless your character is prepared to whip one out, you might want to skip this one.

Rigor Mortis
The most well-known of the mortis family, rigor happens when the body stiffens up. Without getting too deep into the science, if you remember that muscles need ATP to move (by breaking certain bonds), then you’ll see why a lack of ATP causes the muscles to freeze temporarily. It starts right after death, but you likely won’t notice it until about 6-8 hours after death because larger muscles take more time to stiffen.

Unlike other stages of death, rigor mortis isn’t permanent. After an additional 12 hours (up to 24 hours after death), rigor fades as the bonds decompose without ATP’s assistance. A body will be completely out of rigor by 36 hours after death.

Putrefaction
This is when the body starts to decompose. We will save this last stage for other posts since it has its own stages and complications based on weather, method of death, insect activity, predation, and lots of other fun things.