Internal Beveling
Definition
The cone-shaped defect geometry at an entrance gunshot wound in bone: the outer table diameter (entry face) is smaller than the inner table diameter (exit face of the defect), because tensile failure on the inner table produces a wider fracture zone than the compressive punching on the outer table.
- Field
- Skeletal gunshot trauma analysis
- Marks
- Entrance wound in bone
- Shape
- Cone-shaped defect, wider on inner table
- Mechanism
- Tensile failure inward, compressive punching outward
- Contrasts with
- External beveling at an exit wound
Common questions
Why does the inner table fracture more widely than the outer table at an entrance wound?+
Bone is weaker in tension than in compression, so as the bullet punches through, the outer table fails cleanly under compression at roughly the bullet's diameter, while the inner table, pulled apart by tensile stress as the bone flexes outward, fractures over a wider area, producing the cone shape.
Can internal beveling be identified when only bone fragments are recovered, not a whole skull?+
Yes, as long as the fracture margins around the defect are intact on the fragment, the cone-shaped bevel direction can still be assessed, which is why fragment orientation and edge preservation are prioritised during skeletal recovery in gunshot cases.
Related terms
- Bearing Surface Diameter
- The diameter of the projectile face in contact with the bone surface at the moment of impact; smaller than the resulting defect...
- Contact Wound
- A firearm wound produced when the muzzle is pressed against or within a few centimetres of the target surface. Characterised by a...
- External Beveling
- The cone-shaped defect geometry at an exit gunshot wound in bone: the inner table diameter (entry face of the defect) is smaller...
- GSR (Gunshot Residue)
- Primer-combustion products (classically lead-barium-antimony compounds, now also non-lead formulations) deposited on the bone surface at close or contact range; detected by SEM-EDX...
- Keyhole Defect
- An asymmetric gunshot defect produced by a projectile striking bone at a shallow angle; one end shows a conventional beveled entry geometry...
- Puppe's Rule
- The 1994 formalisation of the principle that radial fractures from a subsequent gunshot terminate at fracture lines already produced by a prior...
- Secondary Projectile
- A bone fragment or other material driven at high velocity through adjacent tissue by the primary projectile's passage through bone; produces irregular,...
- Stellate Fracture
- A set of radial cracks extending outward from the main gunshot defect, produced by compressed propellant gas pressure radiating under the scalp...
- Trajectory Reconstruction
- The forensic procedure that integrates the osteological bevel direction, angle-of-impact estimate, and the physical scene evidence to reconstruct the relative positions of...