In this article, Dr Andrew explains that the correct interpretation of stabbing injuries can significantly affect the outcome of a trial.
Evaluation of cutting and stabbing injuries may appear straightforward, but this viewpoint can lead to assumptions which in turn, lead to interpretive errors. This, of course, may have significant ramifications in legal proceedings.
Cutting and Stabbing Concepts
- Incised wounds
- Longer than deep
- Straight or jagged
- Slashing motion
- Stab wounds
- Deeper than long
- Straight or jagged
- Thrusting motion
- Weapon “signature”
- Dismemberment
Note a cutting injury is not the same as a laceration
For example: An emergency room physician identified three open wounds of a driver in a vehicular crash as stab wounds. The driver died in the intensive care unit and given the description of the three injuries in question as stab wounds, intense scrutiny was directed toward her boyfriend who was a passenger in the crash and had sustained minor injuries. The boyfriend was known to local law enforcement as there was a history of domestic violence.
At autopsy, the short, linear wounds showed subtle abrasion along their edges and soft tissue bridging was easily identified in the base of the wounds. These features rule out stabbing as the mechanism of injury. They are clearly blunt impact lacerations, or tears of the skin, sustained as a result of the crash.
Types of wounds
- “Defense wounds”
- Hands
- Forearms
- Rarely lower extremities
- “Wrinkle wounds”
- Interrupted wounds from a single slash
- “Hesitation cuts”
- A not uncommon feature of suicides
- Homicidal incised wounds most commonly involve the neck and may also feature “hesitation cuts”
Wound Signatures
- Skin defect may suggest a weapon or weapon type, e.g.
- Knife, letter opener
- Ice pick, awl, knitting needle, etc.
- Serrated blade
- Screwdriver
- Barbecue fork
- Scissors
For example: The state’s expert witness in a stabbing case opined that given the jagged nature of a stab wound, the weapon had to have a serrated blade such as the knife entered into evidence. An experienced expert for the defense would be prepared to emphatically rebut this testimony based on the fact that stab wounds caused by a serrated blade do not differ in configuration on the surface of the skin from straight blades.
There are certainly ways to discern whether a blade that produced an injury could be serrated, but jagged edges is not one of them.
Chop Wounds
- Present a hybrid of sharp and blunt wound patterns
- Incision of deep tissues with no soft tissue bridging
- Abraded edges due to width of weapon
Interpretive Concepts
- “Langer’s Lines”
- Collagen and elastic fibers that supply skin tone
- When cut, create skin tension that can distort wound shape.
- Solid internal organs may preserve shape and contour of weapon that is lost or distorted on the skin, for example stab wounds of the liver
- Wound length on the skin may exceed the width of the blade.
- A stab wound with external pressure can produce a depth of penetration longer than the length of the blade
For Example: A man was fatally stabbed in a barroom dispute involving several people. The forensic pathologist determined the depth of penetration of the stab wounds varied from two to six inches. One man was charged and indicted.
At trial, the defense elicited testimony from law enforcement that during the course of the investigation a knife, known to be carried by another person was not seized and examined because its blade length was four inches and thus could not have caused a six-inch deep stab wound as described by the forensic pathologist. The forensic pathology expert called to the stand by the defense would be prepared to explain how a four-inch blade can indeed produce a six-inch stab wound, highlighting a significant deficiency of the investigation.
Dismemberment
- Antemortem/perimortem/postmortem?
- Suggestions that person of interest has anatomical knowledge
- Tool mark analysis
For Example: A female torso was discovered in a duffle bag floating on the water near a river bank. Autopsy revealed eight stab wounds with penetration of the lungs and heart. Microseal ® castings were made and preserved of the cut ends of the long bones and neck bones which showed striations suggestive of a tool mark. The preserved pattern was successfully matched to the cut ends of bone recovered six weeks later in a wooded area over 2.5 miles from the riverbed site. In addition, the pattern was identical to a miter saw recovered from the apartment of a person of interest.
Conclusion
An in-depth knowledge of all of these concepts is required to ensure correct interpretation of events surrounding death involving cutting or stabbing injuries.
