Perimortem and Postmortem Trauma

Question 1

perimortem trauma

Answer 1

• occurs at or around death
• bone is still fresh
• shows no evidence of healing
• does not result from taphonomy

Question 2

what are the types of perimortem trauma?

Answer 2

• blunt force trauma
• sharp force trauma
• ballistic trauma

Question 3

what are the characteristics of perimortem trauma?

Answer 3

• 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

Question 4

postmortem damage

Answer 4

• not trauma
• damage to the body that occurs after death
• may occur anytime in the postmortem interval

Question 5

characteristics of postmortem damage

Answer 5

• 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

Question 6

blunt force trauma

Answer 6

• 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)

Question 7

linear fractures

Answer 7

• 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

Question 8

le fort

Answer 8

• midface fracture

- separation of maxilla and/or zygomatics

Question 9

plastic deformation

Answer 9

• permanent deformation of bone (fracture patterns/margins do not line up)
• may be seen in relatively elastic bones

Question 10

depressed fracture

Answer 10

• higher velocity, smaller mass
• may result in crushed outer table
• may result in localized area of detached bone

Question 11

pattern defects

Answer 11

• 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

Question 12

sequence of blunt force trauma

Answer 12

• 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

Question 13

long bone fractures

Answer 13

• bending and compression fractures

- usually complete fractures

Question 14

compound/open

Answer 14

• can also be segmental or comminuted
• sticks our of skin
• increased risk of infection

Question 15

transverse fractures

Answer 15

• right angle to bone’s axis
• displaced or nondisplaced
• line across the bone

Question 16

displaced

Answer 16

bone does not line up perfectly

Question 17

oblique

Answer 17

• oblique fracture of the shaft
• curved/sloped pattern
• at an angle

Question 18

spiral fracture

Answer 18

• oblique fracture around the shaft

- torque applied to long axis

Question 19

segmental

Answer 19

results in 3 fragments

Question 20

butterfly

Answer 20

• type of segmental fracture
• center segment is a triangle
• gives directionality

Question 21

comminuted

Answer 21

• several complex fractures with many bone fragments

- open/closed

Question 22

impacted (buckle)

Answer 22

• compression of 2 fragments of some bone

- common in falls and car accidents

Question 23

greenstick

Answer 23

• incomplete fracture
• bone bent
• common in children

Question 24

sharp force trauma

Answer 24

• 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)

Question 25

what are the three types of sharp force trauma?

Answer 25

• incisions
• puncture/stabbing wounds
• chopping/hacking

Question 26

incised wounds

Answer 26

• length>depth
• v shaped in cross section
• one side llifted relative to the other
• different cuts can be made with the same weapon

Question 27

puncture/stab wounds

Answer 27

• 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

Question 28

chopping/hacking

Answer 28

• 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

Question 29

what are the effects of sharp force trauma?

Answer 29

• radiating fractures
• hinge fracture
• wastage

Question 30

what do deep, small wounds indicate?

Answer 30

puncture tools were used

Question 31

how does rhe assessibilty of the wound effect the object used?

Answer 31

the harder the area is to get to, the more likely a longer blade was used

Question 32

what does chopping/hacking do?

Answer 32

-causes previous marks to be destroyed

Question 33

kerf

Answer 33

walls and floor of a cut mark (like a saw)

-can be used to determine saw type and characteristics

Question 34

breakway spur

Answer 34

• 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

Question 35

false starts

Answer 35

• a kerf cut that does not completlely separate the bone

- can provide you with alot of information about the saw

Question 36

terminal ballistics

Answer 36

study of a projectile when it hits a target

Question 37

caliber

Answer 37

-the cross sectional diameter of the opposite projectile

Question 38

full jacket vs unjacketed

Answer 38

full jackets retain their shape while unjacketed rounds will fragment or collapse

Question 39

entry wound

Answer 39

smaller with internal beveling

Question 40

exit wound

Answer 40

longer and less defined with external beveling

Question 41

what can you learn with trajectory analysis?

Answer 41

• 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