Forensic Medicine · Death & Postmortem Changes

Postmortem Hypostasis (Livor Mortis)

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Definition

Livor mortis (postmortem hypostasis) is the bluish-purple discoloration of the dependent parts of the body due to gravitational settling of blood after death.

Mechanism

  1. Death
  2. Circulation stops
  3. Blood settles in dependent vessels
  4. Livor mortis

Time Course

EventTime
Begins30 min–2 hours
Well developed4–6 hours
Fixed6–12 hours

Distribution

Supine position

  • Back
  • Buttocks
  • Back of limbs

Prone position

  • Face
  • Chest
  • Abdomen

Colour Variations

ColourCause
Bluish-purpleOrdinary death
Cherry redCarbon monoxide poisoning
Bright red / PinkCyanide poisoning
PinkHypothermia
Deep brownNitrate poisoning
Clinical

Medicolegal importance

  • Helps estimate time since death.
  • Indicates the position of the body after death.
  • Indicates whether the body has been moved.
High Yield

The colour of hypostasis is a classic exam question: cherry red = CO poisoning; bright red/pink = cyanide; pink = hypothermia; deep brown = nitrate poisoning.