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Terms in this set (91)

Reading #9
Two components of bone:
1. organic — collagen
2. inorganic/mineral — hydroxyapetite
3 types of fractures caused by gunshot wounds
1. Plug & spall fractures - entrance and exit of bullet
2. Radiating
3. Concentric
Case #1: suicide or homicide
• Soft tissue was confusing to look at because radiating fracture beat the exit wound
• Entrance wound = circular = gun perpendicular to skull
• Results = homicide
Case #2:
• Keyhole defect from a tangential bullet entrance into the skull
• only one bullet killed the defendant, but the trauma to the skull was severe
• the direction of fire determined that people standing on the right may have shot him
Case #3:
• Shot wasn't in self defense because the person was shot in the back of the leg
• pieced the bone together and found a circular entrance wound, but no exit wound
• the bone shattered before the bullet had the chance to pass all the way through
• But the entrance wound proves he was shot from the back of the leg
Blunt force trauma
stress-strain curve
Bone is weaker in tension than in compression and thus bone breaks on far side first
once the bone reaches the failure point, the shearing forces cause the bone to split along the long axis = butterfly fractures
Case #4:
Butterfly fracture tells us which side man's body was hit
the height of the fracture is consistent with the height ot the van bumper and if the van had been breaking hard, the injuries should have been lower
this is consistent with the driver's story that the driver didnt' have enough time to react with the man returning
Case #5:
Did the man jump or was pushed?
Fractures caused by axial loading: teacup fractures
Axial loading fractures are consistent with jumping because of vertical orientation of body which breaks the ends of the long bones
Sharp force trauma
Scapula = rectangular injury - knife was into bone past sharpened edge near knife handle
2nd rib and 3rd rib looked different but they were all caused by the same weapon
o Restoration of damaged facial tissue. Person with sketch book looks at cadaver. Not starting from bone. E.g. if half of skull is messed up fill it in so you can put picture out to public.
o 2D artist's sketch using just the skull. Draw outline of skull and draw in features. Can be done quickly and cheaply and sketch can be enhanced on the computer. Fast, easy and less expensive and sketch can often appear more lifelike than 3D models. Disadvantages:
o 3D model using clay or plasticine. Variation in techniques. American style: simply unite points you've put on the skull with slaps of clay. Put tissue depth markers and fill in spots with clay. European technique: sculpt individual facial muscles. Usually more accurate if done by a skilled artist. Disadvantages: doesn't quite look lifelike and there's something about it that doesn't make it look alive. Tissue depth data from cadaver only provides framework for filling in and doesn't involve details between these points. Nose and ears are difficult to reconstruct because they have so much soft tissue on them.
o Soft tissue features which are key to recognition of an individual and are not directly reflected in the bony structures of the skull and can be problematic. Hairstyle and skin color are very important for recognition and not directly reflected in bony structure of skull. Particular artist might throw a wrench into things.. are they skilled? Does everything they make llook alike? Haven't studied tehcniques between artists and have no way of judging how well this is going. Even a really bad reproduction can be useful by getting your message out there and getting peoples attention
o Future: will remain method of last resort but stuy will continue at low levels.