What's the Difference between Entrance and Exit Gunshot Wounds?

Firearms account for almost two-thirds of homicides in the United States, so unsurprisingly, gun crime is a popular subject for modern crime fiction. 

 

Ballistics and the forensic examination of firearms are complex topics.  When the crime writer Ruth Rendell was at the height of her popularity, she said she no longer wrote about guns in her novels because she always got something wrong. 

 

I'm sure many crime writers feel the same.  So let's turn the subject on its head and start with the results of firing a gun at somebody.  (We'll look at the forensic aspects of the firearms themselves in future blogs).

 

Gunshot wounds can provide a lot of information about what happened in a shooting, such as the make and model of gun, the range of fire, the sequence of fire patterns, the path travelled between entrance and exit wounds, the likelihood of survival and the specific manner of death.

 

What are the basic features of gunshot wounds?

 

Entrance Wounds

 

• Appear as a punched-out hole in the skin.

• Diameter of the wound is usually smaller than the bullet.  This is because the skin is elastic and it retracts after the bullet enters the skin.

• There is an abrasion ring (sometimes called the abrasion collar) around the wound.  This is a ring of skin with the outer layer or epidermis missing, through which small amounts of blood can escape.

• Underlying tissues will not protrude.

• Tattooing or smudging (gunshot residues) may be present around the wound depending on the distance of the shooter from the victim..

Exit Wounds

 

• Exit wounds from low velocity fireams tend to be relatively small.  They can have a variety of shapes e.g. slit-like, X-shaped, irregular.

• Exit wounds from high velocity firearms tend to be large and destructive. 

• A typical exit wound does not have an abrasion ring.

• Underlying tissues may be protruding.

• Tattooing or smudging is always absent.

Of course, the bullet may not actually exit the body, particularly if the ammunition is low calibre.

A more detailed account of the features of entrance and exit wounds, where the entrance wounds are characterised according to the distance from which the shot was fired, can be found here.

Another difference between entrance and exit wounds concerns bloodspatter.

 

Backspatter is ejected from entrance wounds and travels against the line of fire towards the person firing the gun.  If the shooter and gun are close enough to the victim, this blood may be deposited on the shooter's hands or the firearm itself.  Clearly, there is the potential for good associative evidence here.

 

By contrast, forward spatter is ejected from the exit wound and travels in the same direction as the bullet.

If you are a regular reader of my blog, you'll know that I  wuld normally include a video here, to illustrate what I have been writing about.  However, I couldn't find anything appropriate, so instead here is a gunshot wounds presentation from the Health Training Network.   Although the photographs may be upsetting for some of you, the quality of the information is excellent.  I hope you can find something from it to use in your writing.

I'll come back to this subject in future blogs, but do leave a question if there is something that you particularly want to know about gunshot wounds or firearms forensics and I'll try and help you.

I'd love to know how your writing projects are proceeding.  How close are you to publication?  Maybe you're already a published author.  Why not leave a comment at the end of this blog with a link to your latest book?