Blood Vessels After Death: Circulation Ceases, Blood Settles

What Happens to Blood in Vessels After Death

When the heart stops, circulation ceases immediately. Blood does not "drain" from arteries or "fill" veins in an active sense. Instead:

• Blood remains in the vascular bed where it was at the moment of arrest.
• Gravity causes dependent settling (livor mortis / hypostasis) – blood pools in dependent capillaries and venules, creating purplish discoloration of dependent skin.
• Vessels do not actively empty or fill; they simply become static conduits.
• Coagulation begins within minutes to hours (depending on temperature, antemortem conditions) → blood gels in vessels.

Postmortem Changes

• Livor Mortis: Appears 30 min–2 hrs, fixed by 8–12 hrs (blanching test).
• Algor Mortis: Body cooling.
• Rigor Mortis: Muscle stiffening (ATP depletion).
• Decomposition: Putrefaction, marbling (vascular delineation by gas-producing bacteria).

Forensic Relevance

Pattern of lividity helps estimate time of death and body position at/after death. Vessel patency and clot character can indicate antemortem vs. postmortem thrombosis.