Blunt Force TraumaBlunt Force Trauma

Characteristics of InstrumentsCharacteristics of Instruments

SizeSize– length and widthlength and width

ShapeShape– cross-sectional outlinecross-sectional outline

round -- more fx linesround -- more fx lines

angular -- fewer fx lines, distinct edgesangular -- fewer fx lines, distinct edges

– patterned injuriespatterned injuries

WeightWeight– heavy or lightheavy or light

Effects of BFT on boneEffects of BFT on bone

Inbending at the site of forceInbending at the site of force

Outbending around the site of forceOutbending around the site of force

LeFort fracturesLeFort fractures

Ring fracturesRing fractures

Sharp Force TraumaSharp Force Trauma

Sharp Force TraumaSharp Force Trauma

Caused by an implement with an edge or Caused by an implement with an edge or pointpoint

Usually results from compression or Usually results from compression or shearing applied over a narrow focusshearing applied over a narrow focus

Complete discontinuities result from Complete discontinuities result from chopping instruments while infractions chopping instruments while infractions from cutting instruments.from cutting instruments.

Effects of Sharp InstrumentsEffects of Sharp Instruments

PuncturePuncture

IncisionIncision

Cleft/notchCleft/notch

StriationsStriations

WastageWastage

PuncturesPunctures

Caused by pointed instrument directed Caused by pointed instrument directed toward a bone surfacetoward a bone surface– Indentation at point of contact (cone-shaped)Indentation at point of contact (cone-shaped)– Depth of wound depends on instrument and Depth of wound depends on instrument and

causative forcecausative force

IncisionsIncisions

Sharp forces drawn across cortical surfaceSharp forces drawn across cortical surface– Thin lines or V-shaped indentsThin lines or V-shaped indents– Fracture lines are rareFracture lines are rare– Length, width, depth of wound depends on Length, width, depth of wound depends on

size of instrument, amt. of energy and size of instrument, amt. of energy and dimensions of bone impacteddimensions of bone impacted

CleftsClefts

Caused by vertical forces applied by Caused by vertical forces applied by heavy instruments with long, sharp edgesheavy instruments with long, sharp edges– V-shaped notchV-shaped notch– May be accompanied by radiating fracturesMay be accompanied by radiating fractures– Depth depends on force appliedDepth depends on force applied

KnivesKnives

Wound is generally small, clean and sharp Wound is generally small, clean and sharp edged - variation depends on size, type, weight edged - variation depends on size, type, weight and sharpness of the knife (e.g. paring knife v. and sharpness of the knife (e.g. paring knife v. serrated bread knife)serrated bread knife)

Knife wounds are characterized by straight lines Knife wounds are characterized by straight lines - straight lines are seldom found in nature- straight lines are seldom found in nature

Anatomy of a KnifeAnatomy of a Knife

BackBack

SpineSpine

EdgeEdge

PointPoint

RicassoRicasso

CrossguardCrossguard

GripGrip

HandleHandle

MachetesMachetes

Wound is generally Wound is generally long, deep and sharp-long, deep and sharp-edgededged

Machetes can Machetes can penetrate or penetrate or decapitatedecapitate

Other Cutting InstrumentsOther Cutting Instruments

Wound is related to Wound is related to the type of tool used the type of tool used (ice pick, hammer, (ice pick, hammer, screwdriver, pliers)screwdriver, pliers)

Tool may have Tool may have individualized individualized characteristics that characteristics that may tie it to the may tie it to the wound producedwound produced

Other tools, cont. Other tools, cont.

NEVER compromise the integrity of the NEVER compromise the integrity of the evidence by trying to fit the object into the evidence by trying to fit the object into the hole it produced. hole it produced.

One may only say that a wound is One may only say that a wound is consistent with a particular instrument consistent with a particular instrument (unless you have an individualizing (unless you have an individualizing element such as a broken tip that matches element such as a broken tip that matches the suggested tool)the suggested tool)

Wound AnalysisWound Analysis

Description of woundDescription of wound

Instrument characteristicsInstrument characteristics– typetype

cutting, stabbing, choppingcutting, stabbing, chopping

– sizesizeblade length, width, surface contour, sharpnessblade length, width, surface contour, sharpness

Direction of forceDirection of force

Number of traumatic eventsNumber of traumatic events

MiscellaneousMiscellaneous

StrangulationStrangulation– hanging, ligature, manual strangulationhanging, ligature, manual strangulation

FireFire

Chemical TraumaChemical Trauma