Post mortem signs Flashcards
All post mortem changes
- Cooling off - Algor mortis
- Pale colour - Pallor mortis
- Desiccation (drying) - Exsiccatio postmortalis
- Soaking - Maceratio postmortalis
- Stiffness - Rigor mortis
- Postmortem clot - Cruor postmortalis
- Blood sedimentation - Hypostasis postmortalis
- Decoloration - Imbibition
- Self softening - Autolysis
- Destruction/Decomposition - Putrefaction
- Grave wax - Adipocere
Algor mortis
Cooling off
- No metabolic process: no heat prod = thermo-equalization
- Depends on: hair, subcut. fat tissue, temp of the surroundings
- Incr PM temp: overtemperature (heat stroke, septicaemia), spastic muscle contraction (tetanus, strychnine or dinitroortocrezol poisoning)
- Subcut fat tissue: in dogs usually 1°C/hour
Pallor mortis
Pale colour
• Blood is settling to lower parts of the animal: skin and mucous membranes are pale, contraction of small blood vessels
• Not easy to recognize in animals: hair and pigmentation
• Not an infallible sign of death: anaemia
Exsiccatio postmortalis
Desiccation - Extreme drying
• Due to evaporation
• Skin: nasal plate, rostral plate
• Mucous membranes
• Cornea
• Also in alive animal: necrotized skin
• Mumification: complete dehydration of tissues
- dry heat and/or air current: eg. desert, chimney
- function of the putrefactive bacteria is also hampered
Maceratio postmortalis
Soaking • Skin and organs is filled with fluid • Foetuses: aseptic autolysis • Carcasses staying in the water • Also in living animals: flows on the skin
Rigor mortis
Stiffness
• Occurs in all the three kind of muscles: voluntary and involuntary muscles
• Nysten’s rule
Rigor mortis: Heart muscle
– Stand still in diastole
– looks like systole
– Develops fast (30 minutes)
– Lasts for 1 day
Rigor mortis: Smooth muscles
– Quick process (10-15 minutes)
– Lasts for 1 – 4 hours
• intestines, arteries, spleen
Rigor mortis: Skeletal muscles
– 2-4 hours the beginning
– 5-8 hours becomes general
– 24-48 hours starts to disappear
– 48-60 passes off
Onset and duration of RM
• Rapid and short:
– High environmental and/or inner temperature
– Prolonged muscular activity
– Young and elder animals
– Septicaemia, wasting diseases
• Delayed:
– Asphyxial death (notably by carbon monoxide
poisoning)
– Severe hemorrhage, cold surroundings
• Fails to develop:
– In case of degenerative muscle changes
Cruor postmortalis
Postmortem clot
• Dark red, smooth, fleshy with glistening surface
• Not attached to the intima
• Trombocytolysis
– cruor sanguinis – red clot
– crusta lardacea – chicken fat clot
• After death, blood clots in 15-30 minutes
– Heart, large blood vessels
• No clotting in small blood vessels - fibrinolysin
Hypostasis postmortalis
PM blood sedimentation, lividity • Effect of gravity on the blood fluid – in 1 hour –also in the organs (lungs, kidney...) • Livores mortis: PM spots, dark purple • Changing position: special pattern
Imbibition
Discoloration
• Forms:
1. From the blood: hemoglobin imbibition – aorta
– 24 hours - permeable
2. From the gall bladder: bile pigment imbibition
Autolysis (autodigestio)
Self softening • Autolytic ferments of the cell in the cytoplasm – endogenous enzymes • Autodigestio (self digestion) – Gastromalatia: gastric juice – Oesophagomalatia
Putrefaction
Postmortem destruction
• Decomposition products: activity of saprogenic bacteria
• Suffocation supports putrefaction: blood remains liquid
• Intestine – v. portae – liver
• Dissolution into gases, liquids and salts
– Ptomaines (neurine, muscarine, putrescin)
– Gas production – stomach distension
• Under 5oC: putrefaction stops
Rate of putrefaction:
• Rapid:
– Obese (retaining the body heat)
– Warm environmental temp – Hyperemic organs
– Widespread infection
– Injuries (portals of entry)
– Oedematous tissues
• Slow – Lean: exsanguination (dehydration)
