<prompt> Which of the following is not abrasion?GrazeScratchesImpactAvulsion  <response>: Ans. is d i.e., Avulsion Types of abrasion are : ? 1 Scratches linear abrasion : It is an abrasion with legnth but no significant width produced by a sharp object e.g., pin, needles, knife, thorn and nail etc. Point scratch is a very superficial incision produced by a sharp or pointed object not sharp enough to incise but pointed enough to produce scratch. 2 Grazes Sliding abrasionscraping abrasiongrinding abrasion : It is the most common type of abrasion, produced when a broad surface of skin slides against rough surface, e.g., during vehicular accidents. Injury is due to friction. The surface of injury show irregular parallel lines, i.e., furrows or grooves. A violent lateral graze, due to rubbing of skin as in dragging is known as brush burn Gravel rash. Friction burn Scuff or brush abrasion occur due to tangential contact with a smooth surface or when the skin is covered by clothing. It is an extensive superficial, reddened excoriated area without bleeding and with little or no linear mark. 3 Pressure abrasions crushing or friction abrasions : Though it is called friction abrasion, it results from pressure of the object on the body with no or little friction it is a misnomer. It is caused by crushing of superficial epidermis due to inward directed movement of object at around 90deg to skin. Example are ligature marks in hangingstrangulation, teeth bites and nail marks. 4 Impact abrasion Imprint or contact abrasion : It is caused by impact but not pressure with a rough object, when the force is applied at or near 90deg to skin surface. It is depressed below surface unless associated with contusion bruise. 