Early signs of death. EARLY SIGNS OF DEATH Mate Žaja Mentor: A. Žmegač Horvat early changes rigor...

Early signs of deathEarly signs of death

EARLY SIGNS OF DEATHEARLY SIGNS OF DEATHMate ŽajaMate ŽajaMentor: A. Žmegač HorvatMentor: A. Žmegač Horvat

early changesrigor mortiscadaveric rigiditypost-mortem hypostasiscooling of the body

Early changesEarly changesno corneal reflexpupils stop reacting to light“trucking” or “shunting” of the

retinal vessels (fragmentation of columns of blood)loss of intraocular tension

Early changesEarly changesprimary flaccidity

◦ complete loss of tone◦ may retain reactivity◦ may respond to touch and other

forms of stimulation hours after cardiac arrest

◦ focal twitching decreases with time (discharges of dying motor neurons)

Early changesEarly changespaleness of the skin, conjuctivae

and mucous membranes◦fall of blood pressure and cessation

of circulation of the blood◦skin of the face and the lips may

remain red or blue in hypoxic/congestive deaths

Early changesEarly changeshair does not continue to grow

after death because hair follicles die at the same time as the rest of the skin

Early changesEarly changesloss of muscle tone in the

sphincters (voiding of urine)emission of semenregurgitation

◦very common feature of terminal collapse

◦common complication of resuscitation

Rigor mortisRigor mortis

O₂ anoxic pathway of energy production

ATP cell acidity

binding of actin and myosin fibres and formation of gel

stiffness of muscles (isometric contraction)

Rigor mortisRigor mortisfirst the smaller muscle groups

◦around the eyes◦around the mouth◦jaw◦fingers

from the head to the legs

Rigor mortisRigor mortisestimation of time of death

◦it should never be used alonevariable processaffected by temperature

◦the colder the temperature the slower the reactions

Rigor mortisRigor mortistemperate conditions

◦face: 1 to 4 hours◦limbs: 4 to 6 hours

strength increases next 6 to 12 hours

secondary flaccidity: 24 to 50 hours

standard conditions for temperature and pressure

(STP)20°C

101,325 kPa

Rigor mortisRigor mortis

◦ warm and flaccid – less than 3 hours◦ warm and stiff – 3 to 8 hours◦ cold and stiff – 8 to 36 hours◦ cold and flaccid – more than 36

hours

Cadaveric rigidityCadaveric rigidityforensic rarityonset immediately at deathhigh levels of emotional or

physical stress immediately before death◦drowning◦battlefield casualties◦suicidal shooting

possibly neurogenic mechanism

Post-mortem hypostasisPost-mortem hypostasispost-mortem lividity or suggilation

passive settling of blood under the influence of gravity

pink or bluish colour change of the lowest areas

Post-mortem hypostasisPost-mortem hypostasiscessation of circulationrelaxation of muscular tone of

the vascular bedsimple fluid movement within the

blood vessels

Post-mortem hypostasisPost-mortem hypostasismay be absent due to:

◦age – very young or very old◦anaemia◦severe blood loss

may be masked due to:◦dark skin colour◦jaundice◦some dermatological conditions

Post-mortem hypostasisPost-mortem hypostasiscompressed areas remain pale

(blanching):◦surface◦clothing◦body areas

position of the body

Post-mortem hypostasisPost-mortem hypostasiscolour of hypostasis:

◦from pink to dark pink to deep purple◦blue - some congestive hypoxic

states◦cherry pink – carbon monoxide

poisoning◦dark red (brick red) – cyanide

poisoning◦bronze - Clostridium perfringens

infection

Post-mortem hypostasisPost-mortem hypostasishypothermia:

◦usual colour can be unusually pink

◦unusual distribution around large joints and over dependent

areas of the body

Post-mortem hypostasisPost-mortem hypostasisno significant role in determining

time of deathaffected by the movement of the

body (even after normal post-mortem coagulation of the blood)

Cooling of the bodyCooling of the bodyindicator of the time of death

based only on three forensic assumptions:◦37°C at the time of death◦extrapolation of temperature and

applying it to the non-uniform body as a whole (more readings are optional)

◦thermally static environment

Cooling of the bodyCooling of the bodyother variables and factors:

◦mass of the body◦mass/surface area◦body temperature at the time of death◦site of reading body temperature◦posture of the body – extended or

curled◦clothing – material, position on the

body, lack of it◦obesity◦emaciation – lack of muscle bulk◦environmental temperature◦winds, draughts, rain, humidity