ABSTRACT
These are injuries produced when the body is struck with, or strikes, a blunt object. A blunt surface produces injuries by scraping, tearing, shearing, crushing, or ripping. This is in contrast to a sharp force injury, which cuts and separates the tissue as it penetrates. The extent of injury resulting from trauma is a balance between the amounts of force applied, the surface area over which the force is applied, and the duration the force is applied. In general, the greater the force, smaller the area, and shorter the duration, the greater the injury will be. Taking into account that force = mass × acceleration and acceleration = velocity ÷ time, if time decreases and velocity remains constant, acceleration increases. If acceleration increases and the mass remains constant, force increases. So decreased time means increased force and increased damage. The sharper or smaller the surface area, the less force is required to separate the tissue planes and penetrate the body. Blunt objects have a relatively large surface area in contrast to sharp objects, where the cutting edge has a relatively small surface area. It takes much less force to penetrate the skin with an ice pick than with the end of a baseball bat. Examples of blunt objects are fists, shoes, pipes, bricks, bats, hammers, roadways, sidewalks, cars, trains, airplanes, walls, etc. Classifications of blunt-force injuries to skin include abrasions, contusions, and lacerations. These may occur separately but are often present at the same time. As an example, an injury may be described as an abraded contusion with central laceration. Fractures are breaks in the bone as a result of blunt force. Avulsions are splits in the soft tissue or soft tissue planes with or without a laceration as a result of shearing forces.
