Abrasion collar is seen in:
Abrasion collar/ring: Proof of bullet entry wound. Due to spinning motion of bullet. Impoance: Round Abrasion collar - if the bullet hits at right angle to the skin surface. Oval abrasion collar - if the bullet hits at oblique angle to the skin surface Diameter of the entry wound + abrasion collar gives the approximate diameter of the bullet. Grease collar (bullet wipe): A black/gray colored ring is seen lining the entrance wound. Due to the deposition of lubricants, gun oil or lead from the bullet.
Gunshot injury
Stab wound
Drowning
Railway track accident
Ballistics