Signs of Death in Forensic Medicine

A. IMMEDIATE SIGNS (Somatic/Clinical Death)

1. Insensibility and Loss of Voluntary Movement

• Loss of all sensation (touch, pain, temperature) and voluntary motor power
• All reflexes are absent, including the corneal reflex
• Not conclusive alone - can occur in fainting, vagal inhibition, epilepsy, deep narcosis, drowning, electrocution
• Becomes conclusive only when associated with loss of EEG rhythm for a continuous 5 minutes

2. Cessation of Respiration

• Must be complete and continuous
• Stethoscope is placed over the upper portions of the lungs and larynx
• Stoppage for more than 5 minutes is usually irrecoverable
• Historic tests (feather test, mirror test, Winslow's test) are now of historical importance only
• Can occur in: voluntary breath-holding, Cheyne-Stokes breathing, drowning, newborn infants

3. Cessation of Circulation

• Stethoscope placed over the heart apex (left 5th intercostal space)
• No heart sounds for a continuous 5 minutes = evidence of death
• Difficult to hear if sounds are feeble, chest wall is thick, or in emphysema
• A flat ECG for 5 continuous minutes is the definitive evidence
• Historic tests (Magnus test, Icard's test, diaphanous test, fingernail test, heat test) - historical importance only

Suspended Animation (Apparent Death): A state where vital functions are reduced to a minimum but the person is not truly dead. It can occur in voluntary yoga trance, vagal inhibition, narcotic poisoning, hypothermia, drowning, electrocution, shock, and cerebral concussion. Resuscitation by cardiac massage, electric stimulator, or artificial respiration is possible.

B. EARLY SIGNS (Molecular/Cellular Death - within 12-24 hours)

1. Pallor and Changes in the Skin

• Skin on the face becomes pale, ashy-white and loses elasticity within minutes
• Lips appear dark red to black, dry and hard due to desiccation
• Loss of skin turgor and blanching

2. Changes in the Eyes

3. Cooling of the Body (Algor Mortis)

• Algor = coldness; mortis = of death
• After death, heat production stops; body loses heat by conduction, convection, and radiation
• Rectal temperature measured with a thanatometer (25 cm, 0-50°C range)
• Isothermic phase: No fall in rectal temperature for the first ~45 minutes after death (heat gradient not yet established)
• Cooling formula: (37.2°C - rectal temperature) ÷ 0.6°C/hour = hours since death
• In tropical countries (India): average heat loss ~0.5-0.7°C/hour; body reaches environmental temperature in 16-20 hours

• Sunstroke, pontine haemorrhage (disturbed heat regulation before death)
• Tetanus, strychnine poisoning (increased muscle heat from convulsions)
• Acute bacterial/viral infections (lobar pneumonia, typhoid, encephalitis)

4. Postmortem Lividity (Livor Mortis / Hypostasis)

• After circulation stops, blood settles by gravity into dependent (lower) parts of the body
• Produces blue-purple discoloration of skin in dependent areas
• Medicolegal importance:
  1. Reliable sign of death
  2. Indicates the position of the body at time of death (and if the body was moved after death)
  3. Helps estimate time since death
  4. Colour suggests cause of death:
     • Cherry red = CO poisoning or cyanide
     • Bright red = refrigerated body or cold exposure
     • Pink/pale = severe anaemia or blood loss
  5. Distribution may suggest circumstances: hanging (face/neck), drowning, electrocution

5. Changes in Muscles - Primary Flaccidity, then Rigor Mortis

• Stiffening and shortening of muscles due to failure of ATP synthesis after death
• After death, glycogen is temporarily used to resynthesize ATP; when glycogen is exhausted, actin-myosin filaments fuse into a dehydrated stiff gel
• Muscle pH shifts from slightly alkaline to distinctly acid (lactic acid accumulation)
• Persists until autolysis of myosin and actin filaments in putrefaction (secondary relaxation)
• Affects all muscles - voluntary and involuntary; not dependent on nerve supply

C. LATE SIGNS (Decomposition - after 24 hours)

1. Putrefaction

• Decomposition of the body by bacterial action and autolytic enzymes
• Green discoloration begins at the right iliac fossa (proximity of caecum with its abundant bacteria), then spreads
• Body bloats with foul-smelling gases (H₂S, CH₄, NH₃)
• Putrefactive sequence: skin greenish → vessels outline on skin (marbling) → bloating → skin slippage → liquefaction → skeletonization
• Rate accelerated by: heat, humidity, shallow burial, large body size

2. Adipocere Formation

• Saponification of body fat into adipocere (grave wax) - a grayish-white, greasy, soap-like substance
• Occurs in bodies buried in moist/waterlogged environments, or immersed in water
• Requires warm, moist, anaerobic conditions
• Preserves the body shape and may preserve evidence of injuries
• Develops in weeks to months

3. Mummification

• Desiccation and drying of the body tissues
• Occurs in hot, dry, well-ventilated environments (deserts, high altitudes)
• Skin becomes hard, leathery, brownish-black
• Body is well-preserved and may retain identifiable features for years
• In mummification, lividity turns from brown to black

Summary Table: Sequential Postmortem Changes