A rickshaw tyre passed on a 8 year old child. Tyre marks were found on the body. This is an exmaple of :
Imprint abrasion Real confusion in this question is between imprint abrasion and patterned bruising. In both imprint abrasion and patterned brusing there is mark or pattern of the object causing injury. Abrasion is caused by friction and/or pressure between the skin and some rough object or surface. For abrasions to occur some movement along with pressure is essential between the object or instrument or weapon and the skin. In abrasions superficial layers of skin are crushed and damaged. Bruises or contusions are caused by blunt trauma resulting in rupture of small blood vessels which lead to effusion of blood in subcutaneous or subepithelial tissues. However skin is intact in most cases until associated with abrasions. In an accident in which victim is overrun by vehicle, there will be movement and friction between the tyre and skin along with pressure by the tyre leading to imprint or patterned abrasion. There can be intradermal bruises also which are usually associated with patterned objects. So the tyre mark will be primarily an imprint or patterned abrasion (tyre has a pattern because of ridges and grooves) associated with bruises too. Also know? Abrasions are of following types Scratches - a linear injury produced by a sharp object, such as a pin, thorn, nail or tip of any sharp weapon. Graze - An injury which is produced when a broad surface of skin slides or scraps against a rough surface. These are the most common type. Commonly seen in road accidents. Violent lateral (tangential) rubbing against a rough surface can produce abrasion known as 'brush burn' or 'gravel rash'. 'Friction burn' can occur due to tangential contact with a smooth surface. 3. Patterned abrasions: In it pattern of the object causing injury is produced over the skin when the force is applied at right angle to the surface of the skin. Patterned abrasions are produced either by pressure of the object or by impact with a rough object. The .former is called pressure (crushing or friction) abrasion and the latter is known as impact (contact or imprint) abrasion. There can be associated bruising in the surrounding area. Examples are ligature mark, nail and Muir& mark, teeth bite marks, whip marks, radiator, grill or tyre marks in vehicular accidents and muzzle marks in gunshot injuries.
Percolated bruise
Imprint abrasion
Contusion
Patterned bruise