Perimortem and Postmortem Trauma Flashcards
perimortem trauma
- occurs at or around death
- bone is still fresh
- shows no evidence of healing
- does not result from taphonomy
what are the types of perimortem trauma?
- blunt force trauma
- sharp force trauma
- ballistic trauma
what are the characteristics of perimortem trauma?
- no evidence of healing
- uniform coloration of broken and intact bone surface
- presence of depressed fractures, concentric fractures, and radiating fractures
- adherent bone spurs or splinting
- jagged edges
postmortem damage
- not trauma
- damage to the body that occurs after death
- may occur anytime in the postmortem interval
characteristics of postmortem damage
- smaller, more numerous fragments
- right-angles/square fracture margins
- absence of identifiable fracture patterns
- absence of adherent bone spurs or splintering
- coloration differences between fracture margins and adjacent intact bone
blunt force trauma
- caused by a relatively low-velocity force applied over a relatively large surface area
- blunt object strikes body (acceleration trauma)
- moving body strikes blunt object or ground (deacceleration)
linear fractures
- low velocity, high mass
- may emanate from point of impact and radiate outward
- may circumscribe point of impact as the result of outbending
- tend toward path of least resistance
le fort
- midface fracture
- separation of maxilla and/or zygomatics
plastic deformation
- permanent deformation of bone (fracture patterns/margins do not line up)
- may be seen in relatively elastic bones
depressed fracture
- higher velocity, smaller mass
- may result in crushed outer table
- may result in localized area of detached bone
pattern defects
- when BFT defect has impressions of the object that caused the impact
- not commonly found in bone
- can never conclusively correlate a single weapon to a skeletal defect
sequence of blunt force trauma
- later fractures will terminate into earlier ones
- earlier fracture margins may be mapped
- if there are many blows, it may be impossible to figure our the trauma sequence
long bone fractures
- bending and compression fractures
- usually complete fractures
compound/open
- can also be segmental or comminuted
- sticks our of skin
- increased risk of infection
transverse fractures
- right angle to bone’s axis
- displaced or nondisplaced
- line across the bone
displaced
bone does not line up perfectly
oblique
- oblique fracture of the shaft
- curved/sloped pattern
- at an angle
spiral fracture
- oblique fracture around the shaft
- torque applied to long axis
segmental
results in 3 fragments
butterfly
- type of segmental fracture
- center segment is a triangle
- gives directionality
comminuted
- several complex fractures with many bone fragments
- open/closed
impacted (buckle)
- compression of 2 fragments of some bone
- common in falls and car accidents
greenstick
- incomplete fracture
- bone bent
- common in children
sharp force trauma
- essentially blunt force trauma over a very narrow area
- main defect in bone is produced by physical interruption of the bone by a foreign object
- can also create tension/compression fractures of BFT (less likely)
what are the three types of sharp force trauma?
- incisions
- puncture/stabbing wounds
- chopping/hacking
incised wounds
- length>depth
- v shaped in cross section
- one side llifted relative to the other
- different cuts can be made with the same weapon
puncture/stab wounds
- depth>length
- caused by sharp-ended instrument being thrust into tissue
- may provide more info about width, depth, and cross sectional shape of the instrument
chopping/hacking
- caused by instruments like axes or machetes with load applied perpendicular to the sharp edge
- crushing component
- may leave striae that record irregularites along the lebgth of the blade
what are the effects of sharp force trauma?
- radiating fractures
- hinge fracture
- wastage
what do deep, small wounds indicate?
puncture tools were used
how does rhe assessibilty of the wound effect the object used?
the harder the area is to get to, the more likely a longer blade was used
what does chopping/hacking do?
-causes previous marks to be destroyed
kerf
walls and floor of a cut mark (like a saw)
-can be used to determine saw type and characteristics
breakway spur
- projection of uncut bone
- found at the terminal end of the cut after the face of the sae breaks the remaining intact bone
- accompanied by a notch on the opposite oiece
false starts
- a kerf cut that does not completlely separate the bone
- can provide you with alot of information about the saw
terminal ballistics
study of a projectile when it hits a target
caliber
-the cross sectional diameter of the opposite projectile
full jacket vs unjacketed
full jackets retain their shape while unjacketed rounds will fragment or collapse
entry wound
smaller with internal beveling
exit wound
longer and less defined with external beveling
what can you learn with trajectory analysis?
- relationship between the shooter and the victim
- intermediate targets like, if the bullet went through somethign else before hitting the victim, the bullet slowing down wukk cause a different injury pattern
