MSC IV_Forensic medicine - Thermal and firearm injuries.pdf

Thermal and firearm injuries

1. Forensic Medicine
Dr. Suchita Rawat (MSc, MPhil, PhD)

2. Unit 3: Injuries and its Characteristics
Injuries: legal and medical definition; Mechanical Injuries: abrasions, bruises,
lacerations, incisions, stab wounds; Firearm injuries; Self-inflicted and defence
injuries, Fabricated injuries. Thermal injuries: Burn and scalds; Electrical injuries;
Aging of injuries; Ante-mortem versus post-mortem injuries.

3. THERMAL INJURIES

5. Thermal injuries (dry heat/ moist heat)
Source: Aggrawal, A. (2016).
Cause: Flame or hot surface vs. hot liquid or
steam
Site of injury
Edges (absent vs. present sharply defined
edges)
Splashing and trickling (absent vs. present)
Color(black vs. blanched)
Charing and singeing (present vs. absent)
Clothes (burnt vs. wet not burnt)
Scene of crime (ignition accelerants vs. hot
liquids)

6. 1st degree (Erythema
or reddening of skin)
2nd degree
(Blisters/Singeing of
hair/
3rd degree (Epithelium
destroyed/upper
layers of dermis
initiates/Pain fibers
exposed. Most painful
burns
4th degree (Whole
dermis is
destroyed/burns are
painless because pain
fibers are destroyed)
5th degree (Muscles
are destroyed/Burns
are painless due to
destruction of nerve
fibers)
6th degree (Burns
reach up to bone
level/Burns
painless/complete
charring)

7. Thermal Injuries BURNS
●CLASSIFICATION OF BURNS (Pathological
Classification)
Source: Aggrawal, A. (2016).
Source: Aggrawal, A. (2016).

8. EFFECTS OF BURNS
●Surface Area
●Degree of heat
●The Duration of Exposure
●Age ie. Children
●sexi.e. women
●site of burn i.e. neck, face,
trunk and anterior abdominal
wall

9. Rule of Nine:1951 by Dr. A.B. Wallace, a Scottish surgeon
Source: Aggrawal, A. (2016).

10. ●PostMortemChanges(Clothes/FacialFeatures
Crow’sfeet/Pugilisticattitude)
forehead, in the angles of
the eyes, and in naso-oral
folds
Neck: pseudoligature
mark

11. ●PostMortemChanges(Pugilisticattitude)
Source: Aggrawal, A. (2016).

12. Source: Aggrawal, A. (2016).

14. Source: Aggrawal, A. (2016).

15. References
●Aggrawal, A. (2016). Forensic Medicine and Toxicology for MBBS.Avichal
Publication Company, 325.

16. ELECTRICAL INJURIES
Nature of Current (ACv DC)

17. Path of current
In low voltage currents organ at lower level is involved [heart]
In high voltagecurrents organ at higher level is involved
[Respiratory Centre]

18. PM FINDINGS
Electric entry mark characterizsedby a) Joule burn (endogenous burn)
low voltage: British physicist James Joule (1818 –1889)
Crater [most
common] (i)
Round or oval
shallow crater (ii)
1-3 cm in
diameter (iii) has
a ridge of skin
about 1 mm
Metallization: (A)
Aluminum–silvery
(B) Copper –
Reddish brown (C)
Iron –Brownish
black.

19. PM FINDINGS
Crocodile skin: (i) High voltage currents produce extremely high temperatures
(upto4000°C).
Causes keratin of the skin to melt over multiple small areas. On cooling, molten
keratin over these areas fuses into multiple hard brownish nodules [as resolidified
wax]

20. PM FINDINGS
Electric exit mark (1) Site -This mark appears where the body was
earthed or ‘grounded’ (2) More damage of tissues than at entry
marks

21. LIGHTNING
Lightning is an atmospheric discharge of electricity accompanied by thunder, which
typically occurs during thunderstorms, and sometimes during volcanic eruptions or
dust storms. 8 million times/day
Endogenous burns

22. Small, circular, full-thickness burns involving the sides of the soles of the
feet and the tips of the toes. This is the exit mark of lightning.

23. Arborescent burns [, feathering, ferning, filigree burns,
Lichtenberg’s flowers lightning marks].
irregular, superficial, thin,
tortuous markings on this
skin resembling fern or tree
20% -33% cases
* Exogenous burns
Surface burns –2-3
degree

24. Deaths Due to Cold
Hypothermia is a condition in which core (rectal)
temperature drops below 35.0 °C (95.0 °F).

27. FIREARM WOUNDS
●Salient features((1) Types/Confusing
appearances/Wounding from Firearms
i.e. Effects of distance on Firearm
wounds/
Source: Aggrawal, A. (2016).
Source: Aggrawal, A. (2016).

31. HARD VS. LOOSE CONTACT

32. ANGLED CONTACT VS.
INCOMPLETE CONTACT

35. In contact wounds of head –
following features are seen: (i)
Krönleinshot [syn,
Krönleinschuss]-(a) In contact
wounds, occasionally a large exit
wound is produced, and the gases
entering through the wound cause
the expulsion of entire brain out
of the skull

37. Puppe’srulePuppe’sruleisusedtodetermine
sequenceofshotswhenmorethanoneshothave
beenfiredatthecranium.FirstenunciatedbyGeorg
Puppe(1867-1925)ofGermany

38. Sequence of bullets/ difference between exit and entry wound
size
Edges
burning,
blackening/tattooing/gr
ease, abrasion or
contusion collar
Bleeding
wound track colour
radiological or
microchemical
examination of wound
skull)

40. Difference between
Suicidal/Accidental/Homicidal Firearms wound
*site of entrance/distance/direction/number of wounds/hands
of victim/ cadervericspasm/hesitation shots/weapon
Source: Aggrawal, A. (2016).

43. This Photoby Unknown Author is licensed under CC BY-SA