Asphyxiation (Signs Of)

Asphyxiation is a term that describes death that occurs due to the lack of oxygen. This lack of oxygen affects the functioning of the brain, which in turn catastrophically affects the functioning of the remainder of the body.

Asphyxiation can be caused by a number of events. Strangulation, the deliberate squeezing of the neck, can cut off oxygen to the brain. Other accidental or deliberate means of asphyxia include suffocation, where air movement into the body through the nose and mouth is restricted. The classic movie murder image of someone being smothered by a pillow is an example of suffocation.

Another cause of asphyxiation is drowning, where the air in the lungs is replaced by water. The airway can also be blocked when a victim chokes on an object such as a small toy or piece of food. Finally, the airway can also be physically be blocked by hanging, when a person is suspended in the air by a rope or other object wrapped around their throat. Asphyxiation from hanging can occur quickly if the trachea is compressed, or can occur as a result of strangulation if the carotid arteries are compressed.

When investigating a suspected case of asphyxiation, a forensic investigator will look for telltale signs. For example, in the case of strangulation, neck injury could be evident when an autopsy is done on the victim. The squeezing of the neck, whether manually or via an object tied around the neck, can produce distinctive injuries. So will larynx injury resulting from blows to the neck.

Signs of suffocation-related asphyxiation such as strangulation can include bruises and fingernails scratches on the neck, bleeding around the throat, and in some cases, the fracture of the U-shaped hyoid bone at the base of the tongue. Evidence of suffocation may include small red or purple splotches in the eyes and on the face and neck as well as the lungs (petechial hemorrhages).

Asphyxiation may also produce foam in the airways as the victim struggles to breathe and mucus from the lungs mixes with air. This is especially typical in drowning. Other changes can include an enlarged heart and an altered blood chemistry.

By assessing these types of external or internal injuries, the forensic scientist can gain a better understanding if death resulted from asphyxiation and whether the asphyxiation was deliberate or accidental.

see also Choking, signs of; Death, mechanism of; Hypoxia.