Post-Mortem changesMohammed Rjoub
Post-Mortem Changes Seminar Outline Death Rigor Mortis Livor
Mortis/ Hypostasis Algor Mortis/ Body Cooling Decomposition
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 minutes of
anoxia 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 voluntary movement Reflex nervous activity
may persist and circulatory and respiratory function continue
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 those damaged in the CNS)
Brain Dead
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 of discoloration appear at each side of the cornea,
either brown or black.
Tache Noire
Apparent Death a state that mimics death, occurs in:
Electrocution Hypothermia Sun stroke Drowning Drug over dose
(barbiturates) Head injury
Medico-Legal Importance of Death Diagnosis Detect cause of death
Know time of death Social reasons Organ donation Apparent death
Statistical reasons Heritage reasons
Rigor Mortis One of the recognizable signs of death that is
caused by a chemical change in the muscles after death, causing the
limbs of the corpse to become stiff and difficult to move or
manipulate. Death cessation of respiration depletion of oxygen used
in the making of ATP ATP no longer provided to operate the SERCA
pumps in the membrane of the sarcoplasmic reticulum, which pump
calcium ions into the terminal cisternae Calcium ions diffuse from
the terminal cisternae and extracellular fluid to the sarcomere Ca
binds with troponin crossbridging between myosin and actin
proteins. Unlike normal muscle contractions, the body is unable to
complete the cycle and release the coupling between the myosin and
actin, creating a perpetual state of muscular contraction, until
the breakdown of muscle tissue by digestive enzymes during
decomposition. RM initiated when the ATP concentration falls to 85%
of normal
Rigor Mortis (contd)Sequence: 1.Primary muscular flaccidity
2.Generalized muscular stiffness 3.Secondary muscular flaccidity
(cold)(>36h) 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.
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
RM: time estimationWarm Warm Cold Cold Flaccid Stiff Stiff
Flaccid Death < 3 hrs 3-8 hrs 8-36 hrs Death > 36 hrs
Rigor Mortis (contd)M in Iris: Antemortem constriction or
dilation modified May affect the eyes unequal, making the pupils
unequal
M in the Heart: Contracted, stiff LV may be mistaken for LV
hypertrophy
M 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
Rigor Mortis
Cadaveric Spasm Cadaveric spasm also known as instantaneous
rigor, cataleptic rigidity, or instantaneous 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 as the 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
entry into the water. often demonstrates the last activity one did
prior to death and is therefore significant in forensic
investigations, e.g. clinging on a knife tightly
Rigor Mortis vs. Cadaveric Rigor mortis Spasm Cadaveric
spasmOnset delayed after death Onset is instantaneous (2-3 hrs)
Duration is a few hours, Duration approx 12-24 hrs until it is
replaced by rigor mortis Intensity comparatively Intensity
comparatively moderate very strong Mechanism of formation:
Mechanism of formation breakdown of ATP below unknown, but
predisposing critical level factors: Excitement, fear, fatigue,
exhaustion, nervous tension, contraction of Ms at time of death All
muscles of the body are Selected muscles, which affected gradually.
were in a state of contraction at the time of
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
Conditions Mistaken as RM Heat stiffness: Exposure of a body to
intense heat (burning, high voltage electrocution, etc) coagulation
of muscular proteins muscular shortening
Cold stiffness: Exposure of the body to extreme cold (
