Medico-Legal Investigations Blunt Force Trauma. There are Four Main Divisions of Blunt Force Type...

Medico-Legal InvestigationsMedico-Legal Investigations

Blunt Force TraumaBlunt Force Trauma

Blunt Force TraumaBlunt Force Trauma

There are Four Main Divisions of Blunt There are Four Main Divisions of Blunt Force Type Injuries. They are:Force Type Injuries. They are:– Abrasions or scrapes: scratches and grazesAbrasions or scrapes: scratches and grazes– Contusions (leakage of blood from vessels = Contusions (leakage of blood from vessels =

extravation) or Bruises extravation) or Bruises Extra = outside; vasa = vesselExtra = outside; vasa = vessel

– Lacerations or TearsLacerations or Tears– Fractures of Bone(s)Fractures of Bone(s)

Blunt TraumaBlunt Trauma

The severity of blunt The severity of blunt trauma depends on:trauma depends on:– Amount of force Amount of force

delivereddelivered– Time over which the Time over which the

force is deliveredforce is delivered– Region struckRegion struck– Extent of body surface Extent of body surface

struckstruck– Nature of the WeaponNature of the Weapon

Blunt Trauma WoundsBlunt Trauma Wounds

If a weapon breaks on impact less energy is If a weapon breaks on impact less energy is delivered to the bodydelivered to the body

If the body moves with the blow less energy If the body moves with the blow less energy is delivered to the bodyis delivered to the body


The larger the area over which the blow is The larger the area over which the blow is delivered the less severe the injurydelivered the less severe the injury

An object that projects from the weapon will An object that projects from the weapon will deliver all of the forcedeliver all of the force

Rounded portions of the body can sustain Rounded portions of the body can sustain greater injuriesgreater injuries


Abrasions:Abrasions:– An injury in which there is removal of outer An injury in which there is removal of outer

layers of tissue by compression or a sliding layers of tissue by compression or a sliding forceforce

– Indicates EXACT site of contact or impactIndicates EXACT site of contact or impact– In living persons the wound will scab over and In living persons the wound will scab over and

become dry and darkenbecome dry and darken– Postmortem the wound is yellow with a Postmortem the wound is yellow with a

parchment-like appearanceparchment-like appearance


There are three types of Abrasions:There are three types of Abrasions:– ScrapesScrapes– ImpactImpact– PatternedPatterned

What is the Forensic Significance of What is the Forensic Significance of Abrasions?Abrasions?

Indicates violenceIndicates violence Its shape gives an idea about the causal Its shape gives an idea about the causal

instrumentinstrument– Bite abrasions take the pattern of the teethBite abrasions take the pattern of the teeth

Site of abrasion denotes the type of crimeSite of abrasion denotes the type of crime Age of abrasion can be estimated so the time of Age of abrasion can be estimated so the time of

the incident is knownthe incident is known Helps in identification of the assailant as in bite Helps in identification of the assailant as in bite

abrasionabrasion


ScrapesScrapes– A blunt objects takes off the A blunt objects takes off the

top layers of skintop layers of skin– May go as deep as the May go as deep as the

dermis dermis – Leakage of fluids Leakage of fluids

(serosanguineous fluid)(serosanguineous fluid)– The area is reddish brown The area is reddish brown

and forms a scaband forms a scab

BFTBFT

Blunt Trauma WoundBlunt Trauma Wound

Impact AbrasionsImpact Abrasions– The blunt force is perpendicular to the surface The blunt force is perpendicular to the surface

of the bodyof the body Mostly seen over bony processMostly seen over bony process

– EyebrowsEyebrows– CheekboneCheekbone– NoseNose

BFTBFT


Patterned AbrasionsPatterned Abrasions– This occurs when the This occurs when the

object which impacts object which impacts the body leaves an the body leaves an imprint or stamp on the imprint or stamp on the skinskin

– Be aware postmortem Be aware postmortem insect bites may insect bites may resemble patterned resemble patterned abrasionsabrasions


Dating Abrasions is a complicated processDating Abrasions is a complicated process– Scab formation begins in 4-6 hrs and is usually Scab formation begins in 4-6 hrs and is usually

complete in 18 hrscomplete in 18 hrs– The skin begins to regenerate within 72 hrsThe skin begins to regenerate within 72 hrs– Once the scab falls off the skin will remodel and Once the scab falls off the skin will remodel and

become thinner after about 12 daysbecome thinner after about 12 days

What is a Contusion?What is a Contusion?

Bleeding under intact skin due to heavy Bleeding under intact skin due to heavy blunt instrumentblunt instrument– Hemorrhage into the skin, the tissues under the Hemorrhage into the skin, the tissues under the

skin or bothskin or both– Caused by crushing or squeezing of tissueCaused by crushing or squeezing of tissue

Can you Differentiate Ante- and Can you Differentiate Ante- and Postmortem Contusions?Postmortem Contusions?

Yes,Yes, Ante mortemAnte mortem

– Swelling presentSwelling present– Color changeColor change– Not washableNot washable– More tissue infiltration (diffuse)More tissue infiltration (diffuse)


Contusions (Bruising)Contusions (Bruising)– Leakage from ruptured, injured or traumatized Leakage from ruptured, injured or traumatized

blood vessels (cellular leakage as well)blood vessels (cellular leakage as well)– Diffuses out into surrounding tissues Diffuses out into surrounding tissues

(hematoma)(hematoma)– Sufficient BFT must have been applied to tear Sufficient BFT must have been applied to tear

one or more vesselsone or more vessels


Fresh Bruises & Trauma:Fresh Bruises & Trauma:– Age and color a bruise presents depends on certain factorsAge and color a bruise presents depends on certain factors– Bruises can vary in color (depending on person)Bruises can vary in color (depending on person)

Age (Children and elderly bruise easier)Age (Children and elderly bruise easier)– A bruise can appear or disappear depending on:A bruise can appear or disappear depending on:

Oxygen levelsOxygen levels Blood pigment & breakdown of hemoglobinBlood pigment & breakdown of hemoglobin Physical Health AntemortemPhysical Health Antemortem Localized area of injuryLocalized area of injury cancer leukemiacancer leukemia scurvyscurvy AspirinAspirin Anticoagulants (cumadine, heparin, warfarin, etc.)Anticoagulants (cumadine, heparin, warfarin, etc.) TemperatureTemperature HemophiliaHemophilia


BruisingBruising– Bruises can formulate easier in:Bruises can formulate easier in:

Loose tissueLoose tissue FatFat Older adults and/or childrenOlder adults and/or children Women (less muscle mass)Women (less muscle mass) Disease of the vascular systemDisease of the vascular system


Dating Contusions:Dating Contusions:– This is not an exact scienceThis is not an exact science

Hemosiderin in macrophageHemosiderin in macrophage

Bruises usually follow a Bruises usually follow a color pattern but not alwayscolor pattern but not always

– Reddish-purple or Reddish-purple or bluish-purple to violet, bluish-purple to violet, green, dark yellow to green, dark yellow to greenish-yellow and greenish-yellow and then disappearsthen disappears

– The edges of the bruise The edges of the bruise have the oldest colorshave the oldest colors


BruisingBruising– May take minutes to May take minutes to

days to presentdays to present Take photograph Take photograph

incrementally during this incrementally during this timetime

– Bruises can mask Bruises can mask natural colornatural color

– Estimation of age of Estimation of age of bruise can be difficult bruise can be difficult after deathafter death

BFTBFT

What are the Diagnostic Features of What are the Diagnostic Features of Lacerations?Lacerations?

BridgingBridging Abraded EdgesAbraded Edges Edges irregularEdges irregular Contusions at edgesContusions at edges Hair crushedHair crushed


Lacerations (Tears):Lacerations (Tears):– Tears in the skin due to pressure (BFT) are Tears in the skin due to pressure (BFT) are

called lacerationscalled lacerations– Lacerations are distinguished from incisions by Lacerations are distinguished from incisions by

“bridging”“bridging”– Lacerations may or may not imprint the object Lacerations may or may not imprint the object

used to create BFTused to create BFT– There may be no external signs of injury but There may be no external signs of injury but

avulsions may occuravulsions may occur


LacerationsLacerations– The wound usually has The wound usually has

ragged or abraded edgesragged or abraded edges– Wound margins are Wound margins are

irregularly shapedirregularly shaped– BFT injuries often contain BFT injuries often contain

evidence (trace) embedded evidence (trace) embedded in wound in wound Paint, bark, fibers, Paint, bark, fibers,

grease, metals, rubber, grease, metals, rubber, etc.etc.

– May be scrapes and bruising May be scrapes and bruising around the wound as wellaround the wound as well

BFTBFT


Defense Wounds due to BFTDefense Wounds due to BFT– Mainly abrasions and contusionsMainly abrasions and contusions

On back of hands, wrists, forearms On back of hands, wrists, forearms


Fractures of BoneFractures of Bone– Can determine “directionality” of the impactCan determine “directionality” of the impact– Can present as clear breaksCan present as clear breaks– Can present as compound fractureCan present as compound fracture– Can present as hair-line fractureCan present as hair-line fracture


Fractures of the Fractures of the ExtremitiesExtremities– Direct ForceDirect Force

Blunt object impacts a Blunt object impacts a long bone causing long bone causing breaking of the bone on breaking of the bone on the opposite side of the opposite side of impact impact

May be crushing on side May be crushing on side of impact if force is great of impact if force is great enoughenough


Direct ForceDirect Force– Penetrating FracturesPenetrating Fractures

Large force acting Large force acting on a small areaon a small area

– Gun shot woundsGun shot wounds– Focal FracturesFocal Fractures

Small force on a Small force on a small areasmall area

– Bat or pipeBat or pipe


– Crush FracturesCrush Fractures Large force over a Large force over a

large arealarge area– Motor vehicle Motor vehicle

(bumper (bumper fractures)fractures)


Indirect ForceIndirect Force– Produced by a force acting at a distance from Produced by a force acting at a distance from

the fracture sitethe fracture site


Indirect FracturesIndirect Fractures– Traction Fractures – Traction Fractures –

bone is broken by a bone is broken by a violent contractionviolent contraction

– Angulation Fractures – Angulation Fractures – bone is twisted (spiral bone is twisted (spiral fracture)fracture)

– Verticle compression Verticle compression Fractures – oblique Fractures – oblique fracture of long bonesfracture of long bones

BFTBFT

Case StudyCase Study

An elderly woman was discovered lying on her An elderly woman was discovered lying on her back in her sewing room. Rigor mortis was in its back in her sewing room. Rigor mortis was in its early stages. A prominent amount of blood was early stages. A prominent amount of blood was covering her face. At autopsy there were red-blue covering her face. At autopsy there were red-blue contusions to her chest and right side with contusions to her chest and right side with associated lacerations of the spleen and liver. associated lacerations of the spleen and liver. After washing her face, a patterned contusion of After washing her face, a patterned contusion of the left cheek was noted resembling a heel mark the left cheek was noted resembling a heel mark from a shoe or boot. There was no significant from a shoe or boot. There was no significant head trauma.head trauma.


Numerous photographs of the facial contusion was Numerous photographs of the facial contusion was taken. taken.

Within hours of the autopsy, a suspect was Within hours of the autopsy, a suspect was apprehended. He was present in the apprehended. He was present in the neighborhood the last day the woman was seen neighborhood the last day the woman was seen alive. He was wearing tennis shoes which the alive. He was wearing tennis shoes which the authorities confiscated for testing. Fingerprint authorities confiscated for testing. Fingerprint powder was dusted on the soles.powder was dusted on the soles.


A transparency print was made, and the A transparency print was made, and the transparency was placed over the photograph of transparency was placed over the photograph of the facial wound. A criminalist determined the the facial wound. A criminalist determined the comparison was a positive match and the comparison was a positive match and the pathologist agreed. On the basis of these pathologist agreed. On the basis of these examinations the suspect was indicted. No other examinations the suspect was indicted. No other incriminating evidence was found against him. incriminating evidence was found against him. Should these interpretations have been made? Should these interpretations have been made? Was there enough information to indict? If not Was there enough information to indict? If not what other evidence would you want them to what other evidence would you want them to collect?collect?

Case DiscussionsCase Discussions

The approach by both the pathologist and The approach by both the pathologist and criminalist were sound. Both looked at the shoes, criminalist were sound. Both looked at the shoes, transparency and photograph of the wound to transparency and photograph of the wound to make comparisons. A mark on the face can be make comparisons. A mark on the face can be matched with an offending weapon if the pattern is matched with an offending weapon if the pattern is distinct. In this case, both examiners thought the distinct. In this case, both examiners thought the match was perfect because the marks on the face match was perfect because the marks on the face corresponded to the depressed areas of the heel corresponded to the depressed areas of the heel of a shoe.of a shoe.


Matching patterns on a body with objects Matching patterns on a body with objects that may have inflicted them is an important that may have inflicted them is an important part of examining injuries caused by blunt part of examining injuries caused by blunt trauma. These patterns, however, cannot trauma. These patterns, however, cannot be used to determine whether a specific be used to determine whether a specific weapon inflicted injury. weapon inflicted injury.


At best one can determine that a weapon of At best one can determine that a weapon of similar dimension caused damage. Although similar dimension caused damage. Although patterned injuries on the body are not commonly patterned injuries on the body are not commonly matched to a particular weapon, there may be matched to a particular weapon, there may be other material transferred from a victim to a other material transferred from a victim to a weapon such as hair, fibers and blood. Thus, the weapon such as hair, fibers and blood. Thus, the examination suggested that the mark was made examination suggested that the mark was made by a boot with a certain type of sole.by a boot with a certain type of sole.

Medico-Legal Investigations Blunt Force Trauma. There are Four Main Divisions of Blunt Force Type...

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