1. Blunt Force Trauma

3. Wounds • Medico legal divisions of wounds • 1- accidental • 2- sucidal • 3- homicidal • 4- self inflecting

5. Blunt Force Trauma • There are Four Main Divisions of Blunt Force Type Injuries. • They are: • Abrasions or scrapes: scratches and grazes • Contusions orBruises (leakage of blood from vessels = extravation) • Extra = outside; vasa = vessel • Lacerations or Tears • Fractures of Bone(s)

6. Types of wounds

7. Types of wounds

8. Blunt Trauma • The severity of blunt trauma depends on: • Amount of force delivered • Time over which the force is delivered • Region struck • Extent of body surface struck • Nature of the Weapon

9. Blunt Trauma Wounds • If a weapon breaks on impact less energy is delivered to the body • If the body moves with the blow less energy is delivered to the body

10. Blunt Trauma Wounds • The larger the area over which the blow is delivered the less severe the injury • An object that projects from the weapon will deliver all of the force • Rounded portions of the body can sustain greater injuries

11. ABRASIONS There are three types of Abrasions - Impact - Patterned - Scrapes

12. Abrasions • It is the most superficial type of injuries that does not penetrate the full thickness of the skin (usually confined to the epidermis). • Usually caused by blunt force trauma.

13. Characteristics of Abrasions • They are usually not life threatening although they are painful. • They heel without scarring. • Bleeding/Exudation is slight and leads to crust/scab formation. • Might be associated with bruising and laceration

14. Blunt Trauma Wounds • Abrasions: • An injury in which there is removal of outer layers of tissue by compression or a sliding force • Indicates EXACT site of contact or impact • In living persons the wound will scab over and become dry and darken • Postmortem the wound is yellow with a parchment-like appearance

16. What is the Forensic Significance of Abrasions? • Indicates violence • Its shape gives an idea about the causal instrument • Bite abrasions take the pattern of the teeth • Site of abrasion denotes the type of crime • Age of abrasion can be estimated so the time of the incident is known • Helps in identification of the assailant as in bite abrasion

18. Types of abrasions Direct vertical impact: • The force is usually applied vertically onto the skin and causes crushing of the epidermis. • The causative object may stamp it’s shape on the skin. Examples: • Fingernail impression and bite mark, and marks of a vehicle radiator on a pedestrian victim or the pattern of a floor grid on to which a person has fallen.

20. Types of abrasions Tangential impact( brush abrasions): • Loss or scraping of the epidermis due to friction against a rough surface (graze) or a sharp surface (scratch) • Broader surface

21. This example of brush abrasions. It illustrates a motorcycle fatality, where the victim has come in contact with the road surface. • Example of a brush abrasion of the abdomen by scraping along a rough sooted and rusty surface of a metal tank during a fall.

23. Types of Abrasions • Impact Abrasions • The blunt force is perpendicular to the surface of the body • Mostly seen over bony process • Eyebrows • Cheekbone • Nose

24. Types of Abrasions

25. Blunt Trauma Wound Patterned Abrasions • This occurs when the object which impacts the body leaves an imprint or stamp on the skin • Be aware postmortem insect bites may resemble patterned abrasions

26. Patterned Abrasion

27. Types of abrasions Fingernail abrasions • These are important because of their frequency in assaults especially child abuse, sexual attacks and strangulations • Often associated with focal bruises. • Fingernails abrasions are most often seen on the neck, face, and the upper arms and the forearm

28. Fingernail Abrasions

31. Blunt Trauma Wounds • Scrapes • A blunt objects takes off the top layers of skin • May go as deep as the dermis • Leakage of fluids (serosanguineous fluid) • The area is reddish brown and forms a scab

32. Bruising and abrasions along the right side and on the abdomen could have come from a number of causes, including being dragged & pushed down to the ground.

33. Types of abrasions Post mortem abrasions: • Unlike post mortem bruises, artifactualabrasions are common. • They may have been inflicted after death from a variety of causes, including dragging a corpse or buffering in moving water. Some post mortem animal injuries resemble abrasions such as insect bites.

36. Blunt Trauma Wound • Dating Abrasions is a complicated process • Scab formation begins in 4-6 hrs and is usually complete in 18 hrs • The skin underneath the scab begins to regenerate within 72 hrs • Once the scab falls off the skin will remodel and become thinner after about 12 days

37. Importance of abrasions in • forensics • Always reflects the site of impact. • Often indicates the causative agent. • Often indicates the direction of impact. • Helps in determining the time of injury.

39. Importance of abrasions in forensics • Helps in determining the time of injury: • Fresh: hyperemia, oozing serum and usually without bleeding. • Up to 36 hours: hyperemia and soft yellow crust of dried serum. • 2-3 days: dry brown scab. • 6-7 days: falling of scab leaving a red surface which disappears without leaving a scar within 2-3 weeks.