Post Mortem findings and ID of a body Flashcards
What happens after death
Following cardiovascular failure, there is failure of oxygen delivery to the tissues resulting in cellular death.
Energy production ceases and the body cools.
The circulating blood becomes stagnant and settles under the effects of gravity.
The usual body defences fail and it can no longer inhibit the proliferation of bacteria - putrefaction ensues
What time frame gives the “timing of death”
First 18 hours
Factors which influence the rate of body cooling
Body temperature at the time of death: what is the usual temperature and can it vary?
Is the body clothed? What is the nature of the clothing?
Natural insulation of the body!
Convection currents
Environmental temperature
Can stomach emptying be used as a means of measuring time of death
No
Too many factors influence the rate at which the stomach empties, e.g. nature/amount of food, solids vs liquids, stress, certain medication
What is rigour mortis
Stiffening and shortening of muscle fibres leading to rigidity of the musculature and fixation of the joints
what causes rigour mortis
Due to the reduction of adenosine triphosphate (ATP) within the muscles after death
When does rigour mortis become apparent then established
Becomes apparent 5-7 hours after death
Usually full established by 8-12 hours after death
when does the body return to flaccid state
after 36 hours
What is the timing of rigor mortis susceptible to
biologically variability: ambient temperature,
What causes decomposition and Putrefaction
Caused by the action of bacterial micro-organisms; process begins at death, but takes a period of time to become detectable
What variables exist for bacterial micro - organisms decomposition of body
ambient temperature, humidity, “cleanliness” of the environment in which the body lies
What can be seen due to putrefaction of the superficial veins in the skin
Blister formation and tissue swelling, including gas formation in body cavities = Vascular “marbling”
Certain organs relatively resistant to putrefaction and their persistence can be valuable for what
identification purposes
What is mummification
A process of “dry” decomposition, with desiccation of the body and a relative lack of bacterial involvement
Body essentially “dries out”; the facial features and hands/feet may become rigid
Preservation may be remarkable
What is Adipocere formation
Induced by the alteration of fatty tissue within the body into a greasy/waxy or brittle material which frequently remains attached to the bony skeleton and may retain the body structure to some extent
Tends to occur in damp or wet environments, e.g. bodies recovered from water
What is Skeletonisation
The condition when all of the soft tissues of the body have completely degraded
The process is extremely variable: main variables are exposure to meat-eating animals (post mortem animal predation, e.g. rats) and to dipterous larvae
What radio types can be used to age bones
strontium and polonium
What is Post mortem Hypostasis
Represents the pooling of stagnant blood in dependent regions of the body under the influence of gravity more apparent on external than internal organs
When does Post mortem Hypostasis occur
Begins as soon as the circulation of blood ceases, but takes time to become visible, usually about 1-2 hours, and fully established by 6-12 hours
How is post mortem hypostasis useful
Not so useful as a means of timing death, but can be a great help in ascertaining the position of the body after death and can indicate if the body has been moved after death
What is it difficult to distinguish hypostasis against
bruising
haemorrhagic lividity i.e. when the head is hanging of the bed
What is the usually colour of hypostasis
Usually pink/purple in colour
What can cherry red hypostasis indicate
indicator of carbon monoxide poisoning
What can a red brown colour indicate
may be seen with methaemoglobin
What does Post mortem Artefacts
Alteration or damage to the body occurring after death which may mimic genuine processes occurring in life
Examples of post mortem artefacts
Resuscitation (cardiopulmonary resuscitation) Animal predation (land and sea) Traumatic injury (water, motor)
