Emedinews:Insights on MEdicolegal Issues:Abrasion injury in medicolegal cases

Mechanical momentum means mass with velocity discharged into the human body by a moving object or weapon or itself due to impact of moving body against a surface produces injuries over the body. In the first case, the counter force is provided by the body and in the second case, by the rigidity of the object/weapon/surface/wall against which the victim falls by himself or is forced to fall by external reason. In most cases it is seen that the mechanical injuries produced over the body are due to a combination of above two forces. Abrasion is one of the most superficial injuries and involves destruction of the superficial layers of the skin, caused by fall on a rough surface, or being dragged by a vehicle. Abrasions are of different types based on the pattern of the causative force viz. scratches, grazes, pressure, impact or imprint abrasions. A doctor can help legal investigation by his evaluation and documentation of abrasions as below.

• They give an idea about the site of impact and direction of the force.
• They may be the only external signs of a serious internal injury.
• Patterned abrasions may help in relating the wound to the object which produced them.
• The age of the injury can be determined, which helps to corroborate with the alleged time of assault.
• Dirt, dust, grease, sand in the open wounds may connect the injuries to the scene of crime
• Character and manner of the injury may be known from its distribution.
• In throttling, crescent abrasions due to fingernails are found in the neck
• In smothering, abrasions may be seen around the mouth or nose.
• In sexual assaults, abrasions may be found on the breasts, genitals, inside of the thighs, and around the anus.
• Abrasions on the face of the assailant indicate a struggle.
• Abrasions on the victim may show whether the fingernails of the assailant were long, irregular or even broken.