Lecture Notes in Forensic Medicine Derrick Pounder 48pages

Lecture Notes in Forensic Medicine Derrick Pounder 48pages...

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Lecture Notes in Forensic Medicine © Derrick Pounder, University of Dundee - 1 - CHAPTER 1 BLUNT FORCE INJURIES A wound is a disruption of the continuity of tissues produced by external mechanical force. The term injury is used synonymously with wound, but can have a wider meaning and encompass not only damage produced by physical force, but also damage produced by heat, cold, chemicals, electricity and radiation. The English word ‘injury’ derives from the Latin word ‘injuria’ which literally means not lawful. The term lesion originally meant an injury but has now come to be more widely applied to include any area of injury, disease, or local degeneration in a tissue causing a change in its function or structure. Therefore use of the terms injury or wound imply damage from unnatural causes, while the use of the term lesion is non-committal on whether the cause of the damage was natural disease or not. Wounds, or injuries, are generally classified according to their cause as blunt force injuries, sharp force injuries, gunshot injuries, and a miscellany of others, including for example burns. This is the classification followed in this text, and each group of injuries is discussed in successive chapters. A blunt force injury is any bodily damage resulting from forceful contact between the body and a blunt object. The forceful contact most commonly involves movement and impact, with the resulting transfer of kinetic energy. Either the moving object strikes the body as in a blow, or the moving body strikes an unyielding object as in a fall. Less often the physical force is applied more slowly by the pressure of crushing, squeezing, or pinching. Crushing or scraping of the skin produces abrasions (grazes). Bruises occur when the elastic limit, the tolerance, of subcutaneous blood vessels is exceeded so that they tear and bleed. Greater forces are needed to tear the skin to produce lacerations. These three blunt force injuries – abrasions, bruises, and lacerations – may occur singly or together in any combination. Abrasions An abrasion is an area of crushing or loss of skin, or mucous membrane, resulting from contact with a blunt object. Abrasions are typically superficial, trivial injuries which may be overlooked easily but provide useful forensic information. They bleed only slightly, heal quickly and leave no scar. Tangential impact between an object and the skin causes a typical graze in which the superficial skin layers are scraped off and piled up as skin tags at the far end of the injury. The location of the skin tags indicates the relative direction of movement between the object and the body. Broad patches of abrasion are sometimes described as brush abrasions, the frictional element of which gave rise to the term ‘brush burns’, as in for example ‘carpet burns’. They are seen in their most florid form as ‘road rash’, following a motor vehicle collision in which the victim, typically a motorcyclist, slides along the road surface. Trace evidence from the impacting surface may be present
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This note was uploaded on 01/16/2012 for the course BI 200 taught by Professor Potter during the Fall '11 term at Montgomery College.

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Lecture Notes in Forensic Medicine Derrick Pounder 48pages...

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