system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Abrasion collar is seen in:
assistant
The correct answer is  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.