Injuries produced by pointed objects or objects with sharp edges are referred to as “sharp force injuries.” Sharp force injuries are characterized by a relatively well-defined traumatic separation of tissues, occurring when a sharp-edged or pointed object comes into contact with the skin and underlying tissues. Three specific subtypes of sharp force injuries exist, as follows: stab wounds, incised wounds, and chop wounds.
Along with other primitive injury types, such as blunt force trauma, drowning, thermal injury, and other environmentally induced forms of injury, sharp force injuries have been around for a long time. Numerous accounts of deaths due to sharp force trauma are documented in the Old Testament of the Bible, as follows:
“When Phinehas…saw this, he left the assembly, took a spear in his hand and followed the Israelite into the tent. He drove the spear through both of them — through the Israelite and into the woman’s body.” Numbers 25:7-8
“But Jael, Heber’s wife, picked up a tent peg and a hammer and went quietly to him while he lay fast asleep, exhausted. She drove the peg through his temple into the ground, and he died.” Judges 4:21
Even with the advent of more modern injury types, such as gunshot wounds, motor vehicle collisions, medical therapy-related incidents, and injury related to alternating current electricity, sharp force injuries have remained relatively common within the world of death investigation. In fact, as society has become more modern, a variety of new, more “advanced” sharp force injury types have emerged. In this chapter, we will discuss sharp force injuries and the deaths that result from such injuries.
Deaths due to sharp force injuries are less common than those due to blunt trauma, gunshot wounds, asphyxial mechanisms, and drug toxicity. The frequency of such deaths varies from one jurisdiction to another. The most common manner of death associated with sharp force trauma is homicide, followed by suicide. Accidental sharp force injury fatalities do occur but are relatively rare.
A study performed at an urban medical trauma center evaluated the trauma deaths that passed through the emergency department during an 11-year period from 1994 to 2005. Sharp force (stab wounds) accounted for 11% of the cases, compared with gunshot wounds (56%), falls (11%), motor vehicle collisions (9%), assaults (7%), and struck pedestrians (4%).
A report by the Center for Disease Control evaluated violent deaths occurring in 16 states during the year 2006. In the report, a “violent death” is defined as a death resulting from the intentional use of physical force or power against oneself, another person, or a group or community.
Sharp force injuries accounted for 1.7% of all suicides, compared with the top 3 means of suicide: firearms (51.3%), hanging/strangulation/suffocation (22.1%), and poisoning (18.4%). Sharp force injuries accounted for 12.1% of all homicides compared with 65.8% for firearms and 4.6% for blunt trauma.
Overview of the entity
As mentioned above, the term “sharp force injury” encompasses essentially 3 separate but related injury types. Stab or puncture wounds are produced by sharp, pointed objects, wherein the direction of force is more perpendicular to the skin surface, as opposed to tangential or parallel. In most instances, the wound is deeper than it is long on the skin surface.
In contrast, incised or cut wounds are produced by sharp-edged objects, wherein the direction of force is more tangential or parallel to the skin surface, as opposed to perpendicular. In most circumstances, the wound is longer on the skin surface than it is deep.
Chop wounds can be considered a combination of sharp and blunt force trauma, wherein a relatively bulky object with an edge, or a fast-moving object with an edge, impacts the body, resulting in injuries that have features of sharp force trauma as well as those of blunt force trauma.
Indications for the procedure
Sharp force injuries fall under the jurisdiction of the medical examiner or coroner. Although not as common as firearms-related injuries, these injuries are often seen in suicides and homicides. Sharp force injuries are also encountered in the setting of multiple injuries related to motor vehicle accidents.
Detailed examination of sharp force injuries, particularly in homicides, can provide useful information regarding the type of weapon that likely inflicted the wounds. This information can potentially guide the police to the recovery of a murder weapon or it can be used to exclude other implements recovered from a crime scene.