Livor mortis results in a blue to purple discoloration due to blood settling under gravity; when does it typically appear and become fixed?

• A. Appears ½ to 2 hours after death and fixed at 8-12 hours.
• B. Appears 8-12 hours after death and fixed at 1-2 hours.
• C. Appears immediately after death and fixes immediately.
• D. Appears 24-36 hours after death and fixes 48 hours after.

Answer: (A)

Livor mortis arises because, after the heart stops, circulation ends and gravity pulls pooled blood into dependent parts of the body, producing a blue-purple discoloration. This pooling doesn’t appear instantly but becomes noticeable within a short period, typically about half an hour to two hours after death. Over the next several hours, the blood continues to settle and the discoloration becomes fixed as the capillaries lose elasticity and the red cells remain in the dependent tissues. By roughly 8 to 12 hours after death, the lividity is usually fixed, meaning breathing pressure or movement can no longer reposition or blanch it. This combination of onset and fixation timing is why the correct choice matches a appearance window of ½ to 2 hours and fixation by 8–12 hours.