1. Posterior Arch
Mechanism
- axial compression with hyperextension
Associations
- 50% incidence other C1/2 fracture
- i.e. ondontoid fracture
Management
- stable
- soft / philadelphia collar
2. Isolated lateral mass fracture
Mechanism
- asymmetrical axial compression / lateral bend
Fracture which extends between the trochanters of the proximal femur
- lower limit is inferior border of lesser tuberosity
Extra capsular / well vascularized
The key to stability is the posteromedial cortex
>65
Third most common fracture after hip and distal radius
Neck shaft angle 130o
Head retroverted 20o relative to shaft
Anatomical neck (junction of head and metaphysis)