12B3   Wedge fracture, fragmentary wedge

Wedge fractures of the humeral shaft with a fragmentary wedge are classified as 12B3 fractures.

There are two main fragments, a proximal and a distal. After reduction there is some contact between the proximal and distal fragments. There is also a fragmentary wedge.

This fracture type is subdivided:

• 12B3(a) - Proximal 1/3
• 12B3(b) - Middle 1/3
• 12B3(c) - Distal 1/3

Wedge fractures are generally more unstable than simple fractures.

12B3 fractures are rare.

In fractures located in the proximal zone of the diaphysis (12B3(a)), note that the deltoid muscle predominates and may interfere with treatment.

In fractures located in the distal third of the humerus (12B3(c) fractures), the radial nerve is at risk more even than in the other regions.

Image taken from Orozco R, et al. Atlas of Internal Fixation. Paris: Masson; 1998. Used with kind permission.