· After death there is no heat generation, due to loss of all physical, chemical and metabolic functions of the body and there is constant loss of the body heat until it comes to the level of the environmental temperature, as the regulating centre is inactive.
· The rate of cooling depends mainly on the temperature difference between the surrounding and the body (but Newton’s law of cooling is not applicable)
· The body heat is lost by way of conduction, Convection & Radiation.
· After death the surface (Outer Core) temperature falls rather rapidly for some time. But during this period, the loss of heat from the depth (inner core) of the body is rather negligible. This is due to the thickness of the skin and the subcutaneous tissue which are good insulators of heat.
· Site of the body used to record inner core temperature is rectum- 4 inches above anus
· for the first 2 to 3 hrs, no loss of heat or fall of the inner core temperature occurs. Then there is sharp fall of the temperature for about 9 to 12 hrs.After this period the rate of fall again diminishes and the rate tends to zero when the body attains the temperature of the surroundings.
Time
Temp
Factors influencing the cooling of dead body
Ø Atmospheric temperature-
Ø Media of disposal of the dead body- Optimum cooling is earliest in the water media and latest in buried dead bodies. The ratio of rates of fall of the body temperature in water:air:grave::4:2:1
Ø Body built- A thinly built body loses heat rapidly.
Ø Age- Rate of loss of the body heat is comparatively more in cases of infants, young children due to greater surface area compared to volume.
Ø Sex- Female bodies retain heat for a comparatively longer period( due to the distribution subcutaneous fat in excess compared to male)
Ø Clothings/coverings of the body- A body well covered with cloth retains the heat for a longer period.
Ø Posture of the body- body with outstretched limbs losses heat rapidly(due to greater surface area)
Ø POSTMORTEM CALORICITY- condition in which the temperature of the body is raised for the first 2hrs after death. This occurs
· when death is preceded by severe convulsion- Tetanus, strychnine poisoning etc
· if death occurs due to infectious diseases or septicaemia, bacterimia etc (heat produced due to excessive bacterial activity)
· when the heat regulation has been disturbed before death e.g.Sunstroke, some nervous disorders etc.
· Postmortem glycogenolysis – produces up to 140 calories which can increase the body temperature at an instant time by 3.6º F or about 2º C. This is a compulsory phenomenon which occurs in all the dead bodies soon after death.
Medico legal Importance of Algor Mortis
Ø Cooling of the body is a sign of death
Ø from the cooling of the body, time of death can be roughly estimated.
Normal body temp.(98.4º F)- Rectal Temp
Time passed after death in hours = --------------------------------------------------------
Rate of temperature fall per hour
Average rate in temperate region -1.5º F
in tropical region - 0.6 - 0.75º F
Ø Early cooling of the body delays the processes of Rigor Mortis and decomposition
· The rate of cooling depends mainly on the temperature difference between the surrounding and the body (but Newton’s law of cooling is not applicable)
· The body heat is lost by way of conduction, Convection & Radiation.
· After death the surface (Outer Core) temperature falls rather rapidly for some time. But during this period, the loss of heat from the depth (inner core) of the body is rather negligible. This is due to the thickness of the skin and the subcutaneous tissue which are good insulators of heat.
· Site of the body used to record inner core temperature is rectum- 4 inches above anus
· for the first 2 to 3 hrs, no loss of heat or fall of the inner core temperature occurs. Then there is sharp fall of the temperature for about 9 to 12 hrs.After this period the rate of fall again diminishes and the rate tends to zero when the body attains the temperature of the surroundings.
Time
Temp
Factors influencing the cooling of dead body
Ø Atmospheric temperature-
Ø Media of disposal of the dead body- Optimum cooling is earliest in the water media and latest in buried dead bodies. The ratio of rates of fall of the body temperature in water:air:grave::4:2:1
Ø Body built- A thinly built body loses heat rapidly.
Ø Age- Rate of loss of the body heat is comparatively more in cases of infants, young children due to greater surface area compared to volume.
Ø Sex- Female bodies retain heat for a comparatively longer period( due to the distribution subcutaneous fat in excess compared to male)
Ø Clothings/coverings of the body- A body well covered with cloth retains the heat for a longer period.
Ø Posture of the body- body with outstretched limbs losses heat rapidly(due to greater surface area)
Ø POSTMORTEM CALORICITY- condition in which the temperature of the body is raised for the first 2hrs after death. This occurs
· when death is preceded by severe convulsion- Tetanus, strychnine poisoning etc
· if death occurs due to infectious diseases or septicaemia, bacterimia etc (heat produced due to excessive bacterial activity)
· when the heat regulation has been disturbed before death e.g.Sunstroke, some nervous disorders etc.
· Postmortem glycogenolysis – produces up to 140 calories which can increase the body temperature at an instant time by 3.6º F or about 2º C. This is a compulsory phenomenon which occurs in all the dead bodies soon after death.
Medico legal Importance of Algor Mortis
Ø Cooling of the body is a sign of death
Ø from the cooling of the body, time of death can be roughly estimated.
Normal body temp.(98.4º F)- Rectal Temp
Time passed after death in hours = --------------------------------------------------------
Rate of temperature fall per hour
Average rate in temperate region -1.5º F
in tropical region - 0.6 - 0.75º F
Ø Early cooling of the body delays the processes of Rigor Mortis and decomposition
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