Blunt Force Trauma

BLUNT FORCE TRAUMA~ Berti Nelwan by: Dr.EzyanATP

Forensic Pathology• Forensic Pathology is the branch of

medicine which analyses victims of crime scenes medically.

• They are the last physician for the deceased and their role is to discover and interpret the evidence left during the autopsy.

Analysis of Wounds• Not every crime victim is murdered. • Physicians can contribute to proof of

the severity of a crime or that a crime actually occurred in some cases for a living victim.

• Wounds provide evidence of the crime.

Wound Categories• Bruises (or contusions) • Abrasions (or grazes or scratches) • Lacerations • Incised wounds • Puncture (or stab) wounds • Gunshot wounds

DefinitionInjuries resulting from an impact with a dull, firm surface or object.• The deaths resulting from blunt force

trauma occur in a variety of scenarios:– almost all transportation fatalities– jumping or falling from heights, – blast injuries, – Be struck by a firm object, such as a fist,

crowbar, bat, or ball. – Bite wounds and chop injuries may be

considered variants of blunt force trauma, sharp force trauma, or a class of injuries unto themselves.

• Blunt force trauma is routinely involved in cases classified as accidents, as well as in cases of suicide and homicide.– it is important to document evidence of

blunt force trauma in all autopsies– one should not immediately assume that

blunt force trauma is the cause of death• The severity of injuries inflicted as a result

of blunt force trauma is dependent on the amount of kinetic energy transferred and the tissue to which the energy is transferred. (Ek= 1/2 mv2).

• Important: the characteristics of the blunt object and the surface that is impacted.

• Impacts involving a large surface will result in a greater dispersion of energy over a larger area and less injury to the impacted tissues.

• on a small area of a curved surface, such as the head, will cause greater damage than would be caused were that same impact to occur on a flat surface, such as the back, since there will be a more concentrated point of impact on the head.

• The composition, or plasticity, of the tissues impacted also affects the resultant injuries. – For example, a person who is kicked in

the chest may have only minimal injuries to the elastic skin surface, whereas deeper, more solid tissues such as ribs and internal organs may experience fractures and lacerations.

• The another factor affecting the severity of blunt force injuries is the amount of time the body and the impacting object are in contact. – A longer period of contact allows kinetic

energy to be dissipated over a prolonged period, resulting in less damage to the tissues than an equally forceful impact with dispersion of energy over a brief period.

Bruise

Important: Natural Bruises Problems with Skin Bruises• A bruise is "a hemorrhage into tissues

produced by the escape of blood from blood vessels".

• Bruises may be found in the skin, muscles, and internal organs.

• Bruises are typically produced by a blunt force impact, such as a blow or a fall.

• They may also be produced by squeezing or pinching, where the force is applied gradually and then maintained.

Contusions are • discolorations of the skin caused by

bleeding into the tissues from ruptured blood vessels.

• Bruises may occur in a variety of natural diseases in which there is an abnormality of the clotting mechanism of the blood, e.g. scurvy (vitamin C deficiency), leukemia, alcoholic liver disease.

• This bruising is "spontaneous" because the injury which produces it is so insignificant as to typically pass unnoticed.

• The presence of such natural disease will exaggerate the bruising effects of any trauma.

• Delayed appearance • Ageing (relative) • Site of Trauma • Shape of object • Degree of force • Post-mortem bruises • Post-mortem lividity

Classic Causes of Bruises Bruises Site of Trauma• Finger pad bruises: battered babies,

manual strangulation • Different ages: repeated assaults • Shoulders and arms: forceful restraint • Wrists and ankles: dragging • Inner thighs: forceful intercourse • Chest: resuscitation• Bruising is uncommon in Suicides

• The extent of bruising is inversely proportional to the sharpness of the impacting object.

• Bruises may be associated with other blunt force injuries such as abrasions and lacerations.

• As a general rule bruising is not associated with incised wounds or stab wounds where there is a free flow of blood from the cut

• In contrast with abrasions, the location of a bruise does not necessarily reflect the precise point of injury.

• Leaking blood will follow the path of least resistance and gravity.

• The major types of “cutaneous” blunt force injuries are as follows:– Contusion (bruise) – Abrasion– Laceration– Avulsion– Fracture

blood vessels rather than leaking into the tissues.

Delayed Appearance Autopsy and Bruising Degree of Force• Deep bruises may have delayed

appearance at the skin surface. Deep bruises may require as long as 12 or 24 hours to become apparent, and some may never do so

• The more superficial the source of bleeding, the sooner the discoloration will be seen on the skin surface.

• In a living victim, a second examination in one or two days may show bruising.

• In the dead, a further examination one or two days after the original autopsy may show bruises which were not previously seen and reveal previously faint bruises.

Bruising in Deep Tissue1. Possibly life-threatening2. Sometimes no external injury3. Revealed in autopsy

Documenting Bruising1. Photography2. Notes

• The size of a bruise is an unreliable indicator of the degree of force causing it.

• However, a heavy impact is likely to produce a large bruise and a light impact to produce a small bruise.

• If bruising is slight, it is reasonable to assume that the degree of violence was slight.

Determining Degree of Force in Bruise Patterns Causitive ObjectLocation:

• Some areas of the body bruise more easily than others. The face bruises more readily than the hands.

• Bruising occurs more readily in loose tissues and where there is a large amount of subcutaneous fat

• Bruising is less apparent where the skin is strongly supported by fibrous tissue or if the muscle tone is good.

• Age– Infants and the elderly tend to bruise

more easily than young and middle aged adults.

– Infants have loose and delicate skin, and the abundant subcutaneous fat.

– Elderly have degenerative changes in the tissues which support the small blood vessels of the skin and subcutaneous tissues.

• Gender:– Women bruise more easily than men

because they have more subcutaneous fat and this is particularly true of obese women.

• Natural Disease• Skin color

• The shape of the bruise is most likely to reflect the shape of the causative object when the object is small and hard and death occurs soon after injury

• A doughnut bruise is produced by an object with a rounded contour (e.g. baseball).

• Two parallel linear bruises result from a blow with a rod or stick

• Bruises can follow rounded contours if they are caused by a flexible object like a lash

• Bruises produced by fingerpads as a result of gripping are usually larger than the fingerpads themselves.

• The pattern and location suggests the mechanism of causation:– On the neck in throttling– On the upper arms in restraint.

• Such bruises are referred to as patterned.

Aging of Bruises• Color changes a bruise goes through can

give a rough estimate of time of injury• Colors result from breakdown of

hemoglobin from tissueso Dark blue/purple (1-18 hours)o Blue/brown (~1 to 2days)o Green (~ 2 to 3 days) Yellow (~3 to 7 days)

This rate assumes person is healthy, however. • While accurate estimation of the age of a

single bruise is not possible, a fresh bruise can be distinguished easily from one which is several days old.

• Establishing that bruises are of different ages may be of medical importance where there is an allegation of repeated assaults:– Child abuse – Wife beating– Where pre-existing injuries need to be

distinguished from those produced by a recent assault like a chronic alcoholic who was assaulted.

Camps:

red immediate

dusky purple / black soon after

green days 4 -5

Yellow days 7 - 10

resolution days 14 - 15

Glaister:

violet immediate

blue day 3

green days 5 - 7

yellow days 8 - 10


Polson and Gee:

red dark / red black < 24 h

greenish tinge around day 7

yellow around day 14

resolution up to 30 days

Smith and Fiddes:

red immediate

purple black soon after

green days 4 -5

yellow days 7 - 10


Post Mortem Bruises• It requires considerable violence to

produce a bruise post mortem or after death.

• These bruises are smaller relative to the degree of force used.

• Post mortem bruises are most readily produced in areas of hypostasis (post

• The settling, after death, of blood within the blood vessels under the influence of gravity.

• This results in a purplish discoloration of parts of the body that are lower while sparing areas of pressure contact - contact pallor.

• The pattern and distribution of lividity distinguishes it from bruising.

• A body found on its back has livor mortis on the dorsal (back) side with pale areas where the bone contacted the floor

mortem lividity, livor mortis) or where tissues can be forcibly compressed against bone.

Patterns of Injury BLUNT HEAD TRAUMA• Bruises to the knuckles of the hands,

together with bruises of the eyelids, bridge of the nose, cheeks and lips, suggest a fist fight.

• Bruising around the eyes (spectacle bruises) may be produced by direct blows, but also commonly result from a fracture of the base of the skull, e.g. in vehicle collisions or gunshot wounds to the head

• They may also follow blunt impact to the forehead producing jolting of the eyeballs in their sockets with tearing of small orbital blood vessels.

• Injuries in motor vehicle collisions almost invariably include abrasions and lacerations as well as bruises.

• Patterns of injury may allow reconstruction of incidents involving pedestrians or allow distinction between driver and front seat passenger.

• Blunt trauma to the scalp and face can produce contusions, lacerations, and abrasions.

• Battle’s sign — a bluish discoloration of the skin behind the ear that occurs from blood leaking under the scalp after a skull fracture.

• Spectacle hemorrhage (raccoon’s eyes) — a discoloration of the tissues around the eyes usually due to a fracture of the skull.

are three major types of hemorrhages which occur in the skull.1) Epidural hemorrhage — bleeding directly under the skull on top of the dura mater. It is associated with a skull fracture and a torn artery. This type of hemorrhage accumulates rapidly and death may occur quickly.

Subdural hemorrhage — bleeding under duramater on top of the brain. It may or may not be associated with trauma and is caused by torn veins which forces the blood to accumulate more slowly than the epidural bleed.

Subarachnoid hemorrhage — caused by blunt trauma or ruptured blood vessels. It is located directly on the surface of the brain.

Pathologists also look for the presence of coup and contrecoup injuries to the brain to help differentiate between a fall and a blow to the head by a second party.• Coup injury — caused when a moving

object (such as a hammer) strikes a stationary head. The injuries to the brain will be directly beneath the point where the weapon strikes the head.

• Contrecoup injury — caused when a moving head (as in a fall) strikes a stationary object like the floor. The injuries to the brain will be opposite the point of impact.

Abrasions

Definition • A scraping injury to the superficial

layers of the skin (epidermis and dermis) that results from friction against a rough surface

• An abrasion is denuded skin caused by friction. A wound may be either deep or superficial depending on the force and the coarseness of the surface which caused the abrasion.

• Side impact produces a moving abrasion:– Indicates direction. – Trace material (e.g. grit).

• Direct impact produces an imprint abrasion:– Pattern of causative object.

• All abrasions reflect site of impact (in contrast with bruises).

• Assessment of age of abrasions is difficult.

• Post-mortem abrasions - Brown, leathery

BRUSH-BURN ABRASION• One common type of blunt force injury is the

so-called brush-burn abrasion. Brush-burn abrasions are broad, dried abrasions that often have a yellow-orange or orange-red coloration.

• These abrasions are caused by dragging or scraping the surface of the skin against a rugged surface; they are most often encountered when a body slides on pavement. These abrasions are sometimes called "road rash."

Laceration:

A bursting of the skin or other tissues resulting from compression or stretching associated with impact by a blunt object or surface

• Splitting of the skin by the direct crushing of blunt trauma.

• Typically over bone, e.g. scalp, eyebrow, cheekbone.

Distinguished from incised wounds by:– Adjacent abrasion/bruise– Ragged edge– Tissue bridges in depth

Forensic Importance – Not related to object shape – Trace evidence – Relatively little blood loss

(except scalp) Rarely suicidalAvulsion: Fracture:

• A more severe form of laceration in which the soft tissues, musculature, and/or bone are torn away from the normal points of attachment

A break, rupture, or separation of tissue (most often bone) resulting from an impact

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Blunt Force Trauma