1 -1 Post-Mortem Changes Part1

8/3/2019 1 -1 Post-Mortem Changes Part1

1/19

Post-Mortem changes

Mohammed Rjoub


2/19

Post-Mortem Changes

Seminar Outline

Death Rigor Mortis

Livor Mortis/ Hypostasis

Algor Mortis/ Body Cooling

Decomposition


3/19

Death

Cessation of the function of 3 systems: CVS, RS, CNS

Types of Death: Cellular death

cells no longer functioning or have metabolic activities or aerobic respiration.

Different tissue die at different rate; cerebral cortex tolerate only few minutesofanoxia while connective tissue and muscles may survive longer (for hours).

Somatic Death the person is irreversibly unconscious, not aware of surrounding environment

and he is unable to appreciate sensory stimuli or initiate any voluntarymovement

Reflex nervous activity may persist and circulatory and respiratory functioncontinue either spontaneously or with artificial support.

Somatic death= brain death = vegetative state

(all tissue and cells of the body are alive and functioning except for thosedamaged in the CNS)


4/19

Brain Dead


5/19

Indications of Death

Indications of death: Unconsciousness

Loss of all reflexes

No reaction to painful stimuli

Muscular flaccidity Cessation of heart beat and respiratory movement

Eye signs: loss of corneal and light reflexes

Mid dilated position of the pupils

Irregular size and shape of the pupils

Eyelids usually closed incompletely

Tache noire: where the sclera remains exposed, two triangles ofdiscoloration appear at each side of the cornea, either brown or black.


6/19

Tache Noire


7/19


8/19

Medico-Legal Importance of Death

Diagnosis

Detect cause of death

Know time of death

Social reasons

Organ donation

Apparent death

Statistical reasons

Heritage reasons


9/19

Rigor Mortis

One of the recognizable signs of death that is caused by a chemical change in themuscles after death, causing the limbs of the corpse to become stiff and difficult tomove or manipulate.

Death cessation of respiration depletion of oxygen used in the making of ATPATP no longer provided to operate the SERCA pumps in the membrane of thesarcoplasmic reticulum, which pump calcium ions into the terminal cisternaeCalcium ions diffuse from the terminal cisternae and extracellular fluid to thesarcomere Ca binds with troponin crossbridging between myosin and actinproteins.

Unlike normal muscle contractions, the body is unable to complete the cycle andrelease the coupling between the myosin and actin, creating a perpetual state of

muscular contraction, until the breakdown of muscle tissue by digestive enzymesduring decomposition.

RM initiated when the ATP concentration falls to 85% of normal


10/19

Rigor Mortis (contd)

Sequence:

1. Primary muscular flaccidity

2. Generalized muscular stiffness

3. Secondary muscular flaccidity

RM starts to develop about 2-3 hrs after death

Usually its first detected in smaller muscle groups such

as those around the eyes, mouth, jaw & fingers.

It resolves in the same order in which it develops.

It concludes around 36-48 hrs after death


11/19

Factors affecting timing of RM

Environmental temperature:

Cold and wet onset slow, duration longer

Hot and dry onset fast, duration shorter

Muscular activity before death: muscles healthy and robust, at rest before death slow onset, duration longer

muscles exhausted/ fatigued onset rapid, esp in those limbs being used (eg in someone running at

time of death, lower limbs develop RM faster than upper limbs)

increase activity (convulsions, electrocution, lightning) rapid onset & short duration

Age:

extremes of age rapid onset Health:

Cause of death:

asphyxia, pneumonia, nervous des with muscle paralysis & dehydration slow onset

septicemia & poisoning rapid onset, may even be absent, esp in limbs affected by septicimia

emaciated or died of wasting disease rapid onset, short duration


12/19

RM: time estimation

Warm Flaccid Death < 3 hrs

Warm Stiff 3-8 hrs

Cold Stiff 8-36 hrs

Cold Flaccid Death > 36 hrs


13/19

Rigor Mortis (contd)

RM in Iris: Antemortem constriction or dilation modified

May affect the eyes unequal, making the pupils unequal

RM in the Heart: Contracted, stiff LV may be mistaken for LV hypertrophy

RM in Dartos muscle of scrotum: Rigor in Dartos constricts testes and epididymis expulsion of semen

Contraction of seminal vesicles and prostate

Postmortem expulsion of semen

RM in Erector Pilli muscles attached to hair follicles: Goose bumps, hair stands up


14/19


15/19

Cadaveric Spasm

Cadaveric spasm

also known as instantaneous rigor, cataleptic rigidity, orinstantaneous rigidity

rare form of muscular stiffening that occurs at the moment of death,persists into the period of rigor mortis and can be mistaken for rigor

mortis the cause is unknown, but usually associated with violent deaths

happening with intense emotion

may affect all muscles in the body, but typically only groups, such asthe forearms, or hands

seen in cases of drowning victims when grass, weeds, roots or other

materials are clutched, and provides proof of life at the time of entryinto the water.

often demonstrates the last activity one did prior to death and istherefore significant in forensic investigations, e.g. clinging on a knifetightly


16/19

Rigor Mortis vs. Cadaveric SpasmRigor mortis Cadaveric spasm

Onset delayed after death (2-3

hrs)

Duration approx 12-24 hrs

Onset is instantaneous

Duration is a few hours, until it is

replaced by rigor mortis

Intensity comparatively

moderate

Intensity comparatively very

strong

Mechanism of formation:

breakdown of ATP below critical

level

Mechanism of formation

unknown, but predisposing

factors: Excitement, fear, fatigue,

exhaustion, nervous tension,contraction of Ms at time of

death

All muscles of the body are

affected gradually.

Selected muscles, which were in

a state of contraction at the time

of death, are affected.


17/19

Cadaveric spasm in a drowning victim: had grass

from the river bank firmly clutched in the hand

Victim of suicide: The cadaveric spasm

has maintained the position of his arms

after the shotgun has been removed


18/19

Conditions Mistaken as RM

Heat stiffness:

Exposure of a body to intense heat (burning, high voltageelectrocution, etc) coagulation of muscular proteins

muscular shortening

Cold stiffness:

Exposure of the body to extreme cold (


19/19

Medicolegal Importance of RM

Time estimation

Cause of death

Know position

Sure sign of death

Documents

1 -1 Post-Mortem Changes Part1