Hey all! After speaking at the AFN Conference last week on wound/injury terminology, I was approached by many attendees afterward that said they weren't taught these basics as part of their standard training. So I thought I would share some basics here, so that as FNEs, we are using consistent and accurate terminology.
Trauma is divided into blunt force and penetrating. Lets start with blunt force.
Although healthcare providers commonly describe any break in the skin as a laceration, this terminology is forensically and technically incorrect. A laceration is defined as a tear/split in tissue caused by a shearing or crushing force (i.e. blunt force trauma). A laceration is further characterized by incomplete separation of stronger tissue elements, such as blood vessels, tissue strands, and nerves. These stronger tissue elements account for “tissue bridging". In addition, lacerations commonly occur over bony prominences and tend to be irregularly shaped with abraded or contused margins. Lacerations are typically caused by hard objects like a pipe, rock, fist, etc. The crushing mechanism may have an effect on wound healing and scarring and increased risk of infection from the devitalized tissue.
So now, we will move on to penetrating trauma (incisions and stab wounds). An incision is produced by a sharp edge and is longer than it is deep. Incisions can be caused by healthcare staff too (incisions made in the OR). Because of the penetrating mechanism of injury, incised wounds lack tissue bridging and often display very clean, sharp wound edges. Knives, box cutters, and glass typically cause incised wounds. In contrast, stab wounds are penetrating injuries produced by a pointed instrument where the depth of the wound is greater than the length of the wound on the skin. Once again, there is no tissue bridging. So think of long/deep blades. Stab wounds will typically bleed more than incisions, since stab wounds extend beyond just the subcutaneous tissue and typically involve deeper structures like muscle.
An easy way to remember the difference between incision and laceration is to think of a glass beer bottle. If someone takes the bottle and smashes it over someone’s head and the skin is opened, that is a laceration (blunt trauma). If a person breaks the bottle on a table and then uses the piece to slash someone (penetrating trauma) and it is somewhat superficial and longer than it is deep, it is an incision.
If you still are having a hard time grasping this, please feel free to reach out to me and I can send you some pictures as examples from my presentation: christine.foote.lucero@uchealth.org
References
DiMaio DJ, DiMaio VJM. (2001). Forensic Pathology. 2nd ed. Boca Raton, Florida. CRC Press, LLC
Forensic Medicine for Medical Students. Lacerations. Available at: www.forensicmed.co.uk/wounds/blunt-force-trauma/lacerations.
Lynch & Duval (2011). Forensic Nursing Science. 2nd ed. St. Louis, MO. Mosby Inc, Elsevier