on 19.7.05 with 0 comments

  • Lividity: Dark purple coloration (not cyanosis) over dependent areas due to pooling of blood.
  • Starts in 20-30 min as dull red patches then deepen in intensity and coalesce to form large areas of reddish-purple discoloration.
  • Within 60min blood becomes in-coagulable due to the release of fibrinolysins.
  • Clots may persist when the mass of clot is too large.
  • Carbon monoxide poisoning or refrigeration soon may cause "cherry red“ or pink (methaemoglobin).
  • After about 10-12 hours the lividity becomes "fixed" and repositioning the body, will result in a dual pattern of lividity since the primary distribution will not fade completely.
  • The blanching of post mortem lividity by thumb pressure indicates that the lividity is not fully fixed.
  • Distribution of lividity reflects the position at death.
  • Contact pallor or pressure pallor. A supine corpse will display contact pallor over the shoulderblades, buttocks, calves, heels and location of firm fitting clothing, belts or any firm object lying beneath the body.
  • Lividity becomes visible in 1/2 to 4 hours. well developed in next 4 hours and maximum at 8 to 12 hours. *Polson
  • In the heart, lividity may be mistaken for an acute MI, in lungs may appear as hemorrhage or pneumonia. Livid coils of intestine may falsely suggest haemorrhagic infarction.
  • In the areas of lividity the blood is confined to vessels while in bruising the blood infiltrates the tissues and cannot be readily washed away under running tap water.

Category: Forensic Medicine Notes



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