PostMortem changes PostMortem Changes Seminar Outline Death Rigor

Post-Mortem changes

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 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 (cont’d) Sequence: 1. Primary muscular flaccidity 2. Generalized muscular stiffness 3. Secondary muscular flaccidity • RM starts to develop about 2 -3 hrs after death • Usually it’s 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

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 de’s 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

RM: time estimation Warm Flaccid Death < 3 hrs Warm Stiff 3 -8 hrs Cold Stiff 8 -36 hrs Cold Flaccid Death > 36 hrs

Rigor Mortis (cont’d) • 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

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 Spasm Rigor mortis Cadaveric spasm Onset delayed after death (2 -3 Onset is instantaneous hrs) Duration is a few hours, until it is Duration approx 12 -24 hrs replaced by rigor mortis Intensity comparatively moderate Mechanism of formation: breakdown of ATP below critical level All muscles of the body are affected gradually. Intensity comparatively very strong Mechanism of formation unknown, but predisposing factors: Excitement, fear, fatigue, exhaustion, nervous tension, contraction of M’s at time of death Selected muscles, which were in a state of contraction at the time of death, are affected.

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 (<-5⁰C) solidification of subcutaneous fat and muscles, freezing of synovial fluid in joints – Rigor mortis halted until thawing occurs, after which it develops very rapidly

Medicolegal Importance of RM • • Time estimation Cause of death Know position Sure sign of death