Wedge Fracture
Definition
The three-dimensional fracture geometry described by Berryman and Symes (1998): a conical inner-table failure zone wider than the outer-table defect, produced by compressive force transmitted through the diploe from a focal impact.
- Described by
- Berryman and Symes, 1998
- Geometry
- Conical inner-table failure wider than the outer-table defect
- Cause
- Compressive force transmitted through the diploe from a focal impact
- Anatomical structure
- Cranial vault (skull)
Common questions
Why is the inner-table defect wider than the outer-table defect in a wedge fracture?+
The compressive force travels inward through the diploic layer and concentrates as it approaches the inner table, so the cone of failure widens on the inside even though the impact struck the outer surface at a narrower point.
What does a wedge fracture tell an examiner about the direction of force?+
The internal beveling pattern, wider on the side opposite the impact, helps distinguish an entrance-type focal blow from other fracture mechanisms and supports interpretation of impact direction in blunt-force skull trauma.
Related terms
- Bearing Surface
- The area of the striking implement that was in contact with the skull at the moment of force transfer; its geometry can...
- Concentric Fracture
- An arc-shaped fracture encircling the impact zone, produced by outer-table bending tension at a distance from the focal impact; always post-dates the...
- Depressed Fracture
- A fracture where the impacted skull segment is driven inward beyond the elastic limit; the geometry of the depression reflects the bearing...
- Diffuse Loading
- Force distributed over a broad contact area (as from a fall onto a flat surface or a broad-surface blow); produces a broader...
- Focal Loading
- Force concentrated on a small contact area of the skull surface (as from a hammerhead, poker, or stone edge); produces a discrete...
- Hering's Principle
- The 1853 observation that a radiating fracture from a subsequent impact is arrested when it reaches a fracture line produced by a...
- Perimortem Fracture
- A fracture produced at or near the time of death while the bone retains green (fleshed) properties; distinguished by sharp fracture margins...
- Radiating Fracture
- A linear fracture extending outward from the impact point, initiated by inner-table tension as the outer table is compressed; propagates until arrested...
- Wolff's Law
- The principle that bone is deposited and resorbed in response to mechanical loading history. Cortical thickness and trabecular orientation follow principal stress...