1. + distance of the target
Wound severity
Tissue absortion of the KE is the most important and not KE potentialy possessed by the bulet
Characteristic of the missile
Velocity ++
Mass
Ballistic shape
Design and composition
Yaw
Characteristic of the bones
Elasticity
Cohesiveness
Density
Shape
+ distance of the target
+ intermediate target

2. Extrinsic factors
Importance : duration, direction and sequence of forces
Rate of loading
Stress : internal resistance resulting of the application of an external load

3. Intrinsic factors Resistance of bone (haversian bone, medullary bone)
Influence of ageing and pathology (osteoporosis, tumor…)

4. STRESS / STRAIN CURVE FOR BONE
PLASTIC DEFORMATION
FRACTURE
POINT S T R E
ELASTIC DEFORMATION
STRAIN

5. Low rate of loading High rate of loading
Little energy absorbed : creation of linear fractures or no fracture
High rate of loading
Absorption of a high rate of energy : concentric fractrures or comminuted

6. Distant gunshot wound
Abrasion Ring

7. Basic mecanism of Ballistic injuries to bones
Bone (skull)

8. Basic mecanism of Ballistic injuries to bones

9. ENTRANCE Round to oval sharp-edge hole
Outer table
Iner table
Round to oval sharp-edge hole
Large bevelled-out hole (internal bevelling)
Bone
« Cone shape »

10. Entrance : exceptions Beveling on the outer table (?)
Peterson, JFS, External bevelling AND internal bevelling
Return of gaz through the bullet?
Tempory cavity?
Rotation of the bullet?
Angle of the shot?
Shape of the bullet?

11. Entrance : exceptions
Irregular:
Yawing
Tumbling
Re-entrance

12. Exemple of exit Inside Outside
- Sometimes could have blunt trauma shape in case of suture or preexisting fracture
- Minimum beveling

13. Primary fracture
Secondary fracture
Tertiary fracture

14. Morphology of ballistic fracture
Primary fractures
Plug formation
Bevelling formation
« Petalling » in thin bones

15. Entrance/Exit
The magitude of entrance associated fractures (radial, concentric) are often greater than exit associated fractures.

16. Absence of radial or concentric fractures
KE was totaly absorbed by primary fracture
- long distance shot
- low velocity bullet

17. Caliber determination by size of entrance wound ?
Usualy bigger than the caliber because of the yaw

18. Caliber determination
It may never be possible to identify the specific caliber from a simple measurement of the defect
Berryman, Smith, Symes. JFS 1995

19. Fragmentation of the bullet +++
KEYHOLE
defect
Bullet strinking at a very shallow angle produces a combined entrance/exit type effect
Outside
Fragmentation of the bullet +++
Inside

20. Ballistic injuries to long bones

21. « Indirect fractures »?
HV bullet passes near the bone but does not contact it directly
Caused by the high pressure due to the expanding cavity

22. Need to keep bones Evidence for Court
Understand the mechanism of fractures and the path of the projectile
Education

23. CONCLUSION Importance of path/anthropo collaboration
Importance to compare skin and bones
Importance of X-ray (3D?)
Importance to make a meticulous reconstruction

24. CONCLUSION Mecanism of ballistic trauma are the same on all the bones
Importance to differentiate HV trauma and LV trauma
Not realy possible to predict a bullet diameter from the orifice (often smaller than their diameter)