Sunday, 10 March 2013

Causes of Death


Scenario One (Arson Victims)
Arson

When a body is found at the scene of  fire, the corpse is firstly examined for soot in the breathing passage. The presence of soot would suggest that death was caused by asphyxiation, and the victim dies due to the lack of oxygen. In other cases, burns on the corpse with inflamed edges (caused by red blood cells trying to repair the burned skin), would mean that the victim  die from the burns. Wounds and injuries on the body may be a result of the fire, however, if there are signs of underlying bleeding , the victim was already dead before the fire began and the fire was just to cover up another crime.


Scenario Two (Victims Hanged)

A body which is discovered hanging will usually show signs of death due to the lack of oxygen. These include blue skin colour, burst blood vessels in the eyes and inflated lungs. The rope marks on the victim's neck will be compared to the rope found at the crime scene. The slightest difference of the rope impression from the actual rope itself would mean that the rope was not the murder tool.Forensic pathologists will then examine the rope marks on the neck to check if they contain evidently inflamed edges which is a sign that the victim was alive even before being hanged.  All rope markings on the neck should be in the shape of an upside down V, where the knot would cause a wound on the back of the neck, creating the point of the V.

 Strangulation usually breaks the hyoid bone located in the neck, but the bone  will barely be broken during hanging. The breakage of the hyoid would suggest manual strangulation. When strangulation is the case, death may be caused due to the lack of oxygen, but more likely, as a result of the deliberate compression of the neck, causing an inhabitation, the situation where the stimulation of the neck's vagus nerve causes the heart to stop. In cases where the hyoid bone is not broken, but bruising is evident around the nose and mouth, a death is caused by smothering, dying due to the lack of oxygen.

 

 

Scenario Three (Victims Drowned)

Dead bodies discovered in water are eamined if water is present in the airway of the victim and if the lungs had swollen up. If such indications are noticed, the victim did actually die due to drowning. If bleeding had occurred in the lungs, it suggests that there was a struggle during the drowning.
mariovittone.com
drowning


 

 
 
 

Marks of Violence
 
Internal/External Examinations
During an autopsy, there may be no external signs that the victim suffered from a brain haemorrhage. Brain scans are the only way to reveal the fatal clots that may have been caused by a blow to the head. Changes in the appearance of skin colour may also lead to solving the crime.

Bruising
bruise
Bruising on the skin occurs when blood vessels are broken by  forceful contact with the skin, usually by something blunt. The shape of the bruise will then be able to tell which direction the blow was received from and colour of the bruise can indicate how long ago the injury had occurred. As bruising heals, it turns red-purple, to brown, to green and lastly, to yellow.  Strangulation also leaves bruising. The hands, cords and ropes usually leave a distinct mark around the neck in the shape of pattern on strangling agent. If the strangling agent is a very soft material, it may leave little or even no marks, but the dissection of the neck area is able to show tissue bruising beneath the skin.Bruising is an inaccurate way to decide how the victim had met their fate, as interpreting bruising is different for every person, due to the fact that people bruise at different rates and bruising continues for a short while after death.


Cuts

The shape of a cut on the skin can show whether the weapon had one or two cutting edges, while angle and direction of cut can reveal whether a death was accidental or intentional. For example, committing suicide would leave a wrist cut cutting towards the knife-carrying hand. Also, the deepness of the wound can show how much force was used during the stabbing and can also determine whether the criminal had  intended to kill his victim.                                                         
Cut


Gunshots
 Size of wound can be a guide to the type of gun and bullets used and burn marks around wound is able to reveal whether the victim was shot at close range or from a distance away. A weapon fired close to the victim makes a single, big wound while a weapon fired from far away leaves many individual wounds.

Burns
Burns discovered on the body might be the cause of death, as the body may go into shock and die if untreated. Small burns on the body might have been a result of electrocution,, but a dose of electric current may cause severe blistering where the electric current had first met the skin. Electrocution occurring in water often leaves the body unmarked.

Assault
Assault leaves injuries such as ruptures, internal bleeding and broken bones. During an assault, the abdominal organs are the ones that are easily damaged as the body offers no protection for them. Ruptures in liver and spleen cause wounds in the bladder and stomach. The victim usually dies from internal bleeding into the abdominal cavity rather than the failure of the organs. Broken bones occur most commonly in the nose, jaw and ribs because these bones are more fragile than the bones in the legs and arms.


 

Determining cause of death


Death is usually caused by one of these three ways:
Coma (failure of brain)

Syncope (failure of heart)

Asphyxia (failure of lungs)


·        

Coma is usually cause by one of these four ways:

-Fracture of the skull which compresses the brain. In homicides, this is usually caused by a direct head injury by a blunt implement.

-Some poisons

-Some narcotic and hypnotic drugs

-Medical conditions such as cerebral haemorrhage and brain tumour.


Syncope


-Natural heart failure may be caused by several degenerative diseases and they can be aggravated by shock.

-Some poisons

-Direct injury to heart


 Asphyxia (lack of oxygen) is cause by:

-Breathing air that has insufficient oxygen content

-Obstruction of oxygen supply by air passages being blocked

-Pressure on chest or abdomen which prevents breathing

-Paralysis of respiratory system by electric shock or poison




Common specific causes of death include:

·         Bludgeoning with a blunt instrument. It is only likely to be fatal if is on the head. Death is usually from skull fracture pushing fragments of bone into the brain.
·         Burning - usually killed by too much smoke inhalation. Bodies exposed to intense heat are stiffened. As burning is sometimes used to cover up other crimes, the presence of burns on the body need not imply that this was the cause of death.
·         Drowning - kills by asphyxia, as the lungs fill with liquid. Post-mortem signs:
-Fine white foam at nostrils and mouth

-Wrinkling of skin if it had been in water for quite a while.

-Water in stomach

-Also look for signs of alcohol and drugs which may have caused accidental drowning.





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