Blunt Force Trauma DEFINITION OF WOUNDS Medical definition

Blunt Force Trauma

DEFINITION OF WOUNDS Medical definition: Disruption of the continuity of the tissues produced by external mechanical force. Legal definition: Breach of the full thickness of the skin

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

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

Types of wounds Abrasions Lacerations Bruises Incised Wounds

Types of wounds

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

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

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

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

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.

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

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

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

Types of abrasions Direct vertical impact: 1) The force is usually applied vertically onto the skin and causes crushing of the epidermis. 2) 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.

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

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

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

Types of Abrasions

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

Patterned Abrasion

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

Fingernail Abrasions

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

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.

Types of abrasions Post mortem abrasions: • Unlike post mortem bruises, artifactual abrasions 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.

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

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.

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.