Back To CoursePathophysiology Textbook
20 chapters | 274 lessons
As a member, you'll also get unlimited access to over 75,000 lessons in math, English, science, history, and more. Plus, get practice tests, quizzes, and personalized coaching to help you succeed.Try it risk-free
I'd like to introduce you to the mortifying Mortis Brothers.
They are, from left to right, Pal, Al, Rig, and Liv Mortis. They are all involved in postmortem changes, or changes that occur to a body following death.
They are pretty disgusting and may cause some of you to be a bit queasy in certain parts of this lesson, but if you're a fan of CSI, then you'll definitely enjoy this lesson and its look into the four fundamental ways in which a body changes after a person's death.
Our first brother is called Pal, or pallor mortis, which refers to the paleness of a person's skin associated with death. I think that's pretty easy to remember. This pallor, or paleness, happens very rapidly, within a minute or so, after death. That's because the heart stops pumping blood when a person dies.
Once the blood stops circulating, it begins to pool away from the edges of the skin towards the dependent regions of the body, resulting in whitening of the skin. This will be an important point to recall towards the end of this lesson.
Our second brother is Al, who is more technically known as algor mortis. No, by the way, he's not related to Al Gore, and he didn't invent the Internet. Algor mortis refers to the cooling of the body after death.
'Algor' refers to coldness, while 'mortis' refers to death. But an easier way I remember that algor mortis refers to the cooling of the body after death is that 'algor' sounds like 'Al Gore.' If you're a fan of Al Gore, then you'll remember it because Al Gore would want our planet to cool down a bit so we don't suffer from the nasty after-effects of global warming.
The reason the body begins to cool after death is because the energetic processes that occurred while someone is alive stop. It's akin to shutting down the coal plant that provides you with power. No coal means no electricity, which means no heat for your home.
The body will cool to the ambient, or surrounding, temperature of its environment. The rate of cooling will depend on many factors, such as:
and many other factors that must be taken into consideration by a crime scene investigator in order to help use this clue to establish a potential time of death, although often times the body is found too late to use algor mortis as a clue for establishing the time of death.
Our next brother is Rig, or rigor mortis to be more precise. Rigor mortis refers to the contraction of muscles after death. That whole stiff dead man thing you've probably heard about - that's rigor mortis.
The stiffening of the muscles begins about 1-6 hours after death and lasts about a couple of days.
However, these time frames are all relative and are influenced by factors such as:
And so on. These are all things that forensics teams must take into consideration!
This contraction of musculature occurs as a result of the depletion of the body's energy currency, ATP. Once the muscles contract and the body's ATP and glycogen stores are depleted, the muscles cannot relax until the body begins to break down and decay.
The way to quickly remember what rigor mortis refers to is to simply pronounce the first word, 'rigor.' It clearly resembles via its first three letters the word 'rigidity.'
Finally, we get to meet Liv, or livor mortis. Livor mortis refers to the gravitational pooling of blood in the dependent portions of the body. Livor mortis is sometimes also called 'hypostatic congestion' among other names.
The pooling of blood towards the down side of a person begins within an hour after death and depends on how compressed the local capillaries may be. Maximal pooling of this blood occurs around 12-24 hours after death, after which point the movement of the body towards different positions will not change the discoloration of the body. Again, these timelines are relative to many factors pertaining to the body and the environment.
Overall, though, this discoloration manifests itself in a purple-red-blue appearance, again, on the down side of the body. So, if someone was killed and was lying on their right side, then the body's blood would pool toward the right side of the body. This can later be seen as purple-red-bluish, bruise-like areas on the person's right arms, leg, and so forth underneath the skin that wasn't in direct contact with the ground. The areas in direct contact with the ground would be pale because the pressure from the ground would collapse the capillaries running near the surface of the body, forbidding blood from pooling in them.
If a murderer came back a day or two later and moved the body by placing it on its back, crime scene investigators would be able to tell that the body was moved since the new downside, the back, would not be discolored due to livor mortis at all.
So, I hope this lesson didn't make you want to vomit due to its disgusting nature. If it did, then perhaps the medical or forensics field is not exactly your cup of tea.
Let's review our brothers and what they stand for one last time. Our first brother is called pallor mortis, which refers to the paleness of a person's skin associated with death. Algor mortis refers to the cooling of the body after death, while rigor mortis refers to the contraction of muscles after death. Finally, we got to meet Liv, or livor mortis. Livor mortis refers to the gravitational pooling of blood in the dependent portions of the body. Do recall that all of the timeframes associated especially with livor mortis and rigor mortis are slightly different in each scenario depending on many different factors!
Upon completing this lesson, you should be able to:
To unlock this lesson you must be a Study.com Member.
Create your account
Already a member? Log InBack
Did you know… We have over 160 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.
To learn more, visit our Earning Credit Page
Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.
Back To CoursePathophysiology Textbook
20 chapters | 274 lessons