Bodies From Fire Flashcards

Question

Features of sponatneous human combustion

Answer 1

``` Not true spontaneous combustion May be natural death with PM burning Ignition source usually cigarette Slow, smouldering fire - hours - clothing acts as wick - body fat acts as fuel Fire damage localised to body and surroundings ```

Answer 2

``` 800-900°C Takes 2-3 hours Cremation is not complete Leaves 1-1.5kg white calcinated bone and ash - ends of long bones - skull fragments - pelvic fragments ```

Answer 3

Thermal Electrical Chemical

Answer 4

``` Moist heat - steam - hot liquid Resembles first or second degree burns - red swollen, blistered painful - well demarcated - no singeing, charring or carbonisation Patterns due to splash, tipping, trickling or dipping - areas spared by clothing ```

Answer 5

``` Sparing in areas covered by clothes Flow - gravity and cooling Splash - thrown, often irregular Glove and stocking - dipping of hands and feet Doughnut - sitting in bath - sparing of contact areas - buttocks and knees ```

Answer 6

``` Tissue damage depends on - voltage applied - resistance of skin - wet or dry - resistance of tissues - current which flows - duration of contact - deep burning Voltage = current x resistance Duration of flow is also important - 50-80mA across heart for a few secs is usually fatal ```

Answer 7

When body forms part of electrical circuit Current flows from entry to exit along path of least resistance Dry skin has a high resistance - high heat on entry/exit Blood vessels and nerves have low resistance Vital area - hand to opposite foot - across chest - heart -> VF - across chest - respiratory muscle paralysis - through head - cardiac and respiratory centre in brain stem

Answer 8

Accidents are common Invisible risk - most deaths accidental Wet hands and surfaces increase risk - bathroom and kitchen Suicide is rare 240V, 50Hz alternating current is very dangerous - likely to cause cardiac arrhythmia and arrest (VF) - spasm of hand and forearm muscles causes spasm and hold-on Prolonged contact causes burning - continues PM

Answer 9

``` Often no visible mark - broad area of contract - moist or sweaty skin Burn at entry site - often hands - current flow easily through tissues - diffuse current pathway - > no internal injury - muscles and verves readily paralysed Burn at exit site - often feet ```

Answer 10

Collapsed blister Surrounding zone of erythema Peripheral ring of pallor Metallisation of skin

Answer 11

``` Sparks leap gap between source and entry - distance depends on voltage - 1000V -> few mm - 5000V -> 1cm - 100 000V -> 35cm Melts epidermal keratin which cools to form a localised hard brown nodule Multiple spark lesions from HV - crocodile skin Clothes may ignite ```

Answer 12

``` Hundreds of deaths worldwide - particularly tropics Charged cloud discharges to earth - direct strike over/through victim - indirect transmission - crane driver - side flash from other objects Gigantic voltages and current flow - kA Always accidental Scene may arouse suspicion Clothing scorched and torn by blast Skin burn near metal objects Arborescent marks ```

Answer 13

``` Pylons and sub-stations - accidents at work Spark lesions HV may fling victim clear Prolonged contact causes gross burning ```

Answer 14

``` Due to corrosive acids and alkalis Usually accidental Suicidal ingestion of corrosives is rare - pain, vomiting - SOB, difficultly swallowing - perforation of oesophagus or stomach - shock Tissue damage depends on - nature of chemical - quantity applied - strength/concentration - duration of application ```

Answer 15

Acids with pH < 2 produce coagulative necrosis - nitric acid -> yellow brown scab - sulphuric acid -> black-brown scab - hydrochloric acid -> white to grey scab - carbolic acid -> light grey to light brown scab

Answer 16

``` Alkalis with pH > 11.5 produce liquefactive necrosis Penetrates more deeply than acid burns Caustic alkalis - caustic soda - NaOH - ammonium hydroxide - AmOH4 Grey white mucoid burn ```