Post Mortem Changes Flashcards
When can post mortem changes appear?
Early
Late
What are examples of early post mortem changes?
Temperature
Hypostasis
Rigot mortis
What are examples of late post mortem changes?
Decomposition and autolysis
Mummification
Adipocere
Skeletonisation
What does the human body cooling not obey and why?
Newton’s law of cooling as metabolic heat production does not occur uniformly
How long does heat production occur after death?
For a variable time
What is the rate of cooling proportional to?
The difference in temperature between the body surface and its surroundings
What are some factors that affect body cooling?
Initial body temperature
Strenous activity
Body dimensions
Ambient temperature
Clothing and covering
Air movement and humidity
Medium around the body
Posture
Haemorrhage
What is hypostasis?
Gravity pulls blood to the lowst accesible area when circulation ceases
What does the pattern from hypostasis depend on?
Posture
What can sometimes be helpful to identify the cause of death in relation to blood?
The colour of hypostasis
What is rigor mortis?
Stiffening and shortening of muscle fibres leading to rigidly of the musculature and fixation of the joints
What does rigor mortis happen due to?
Reduction of ATP within the muscles after death
What are factors affecting the timing or rigor mortis?
Temperature
Physical activity before death
Body temperature at time of death
Convulsions
Electrocution
What are the 2 kinds of decompostion?
Putrefaction (microbiological degradation)
Autolysis (endogenous proteolytic degradation, due to enzymes)
What is putrefaction decomposition?
Microbiological degradation
What is autolysis degradation?
Endogenous proteolytic degradation due to enzymes
What are variables that affect decomposition?
Ambient temperature
Humidity
Cleanliness of the environment the body is lying in
What is mummification?
The process of dry decomposition, with desiccation of the body and a relative lack of bacterial involvement
What a happens to the body during mummification?
It essentially dries out
What is adipocere?
Induced by the alteration of fatty tissues within the body into a greasy/waxy or brittle material which frequently remains attaches to the body skeleton and may retain the body structure to some extent
When does adipocere tend to happen?
In damp or wet environments
What is skeletonisation?
The condition when all of the soft tissue of the body have completely degraded
What is useful to age bones?
Radioisotopes
Why can the time of death not be estimated with any any accuracy?
Due to so many variables
What are the basic rules of thumb for estimating the time of death?
0-12 hours (body temperature is most useful, 1oC drop per hour)
24 hours (rigor mortis and hypostasis)
48 hours to 3 weeks (putrefaction)
Months to years (adipocere, mummification, skeletonisation)
