When does Livor mortis begin?

Livor mortis, also known as postmortem hypostasis, refers to the settling of blood in the lower parts of the body after death due to gravity. This phenomenon begins when the heart stops pumping blood, which halts circulation throughout the body. As a result, blood starts to pool in the capillaries and small veins, primarily in the areas closest to the ground.

Understanding this process is crucial, especially in forensic science and investigations related to cause of death, as the timing of livor mortis can help establish a timeline for death. It is typically noticeable within a couple of hours after death and can provide valuable clues regarding the position of the body at the time of death, as well as an estimation of the time elapsed since death occurred.

The other options do not accurately describe the onset of livor mortis. It does not begin when the heart is actively pumping, nor is it affected by body movement from the death scene or exposure to air, as these factors come into play later in the process or do not directly influence when livor mortis starts.