Emedinews:Insights on Medicolegal issues:The duration of abrasion is roughly estimated as fresh when it is bright red

Mechanical momentum means mass with velocity discharged into the human body by a moving object or weapon or the 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 itself or 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 two above forces.

An abrasion is one of the most superficial injuries and means destruction of the superficial layers of the skin, caused by fall on a rough surface, by being dragged by a vehicular accident. According to the pattern of its causing force, abrasions are termed as scratches, grazes, pressure, impact or imprint abrasions. The duration of abrasion is roughly estimated as fresh when it is bright Red /½ day – 1day – Bright scab (covering) 2-3days – Reddish Brown covering and on 7th day - Almost normal.

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