12B2   Wedge fracture, intact wedge

Wedge fractures of the humeral shaft with an intact wedge are classified as 12B2 fractures.

There are three fragments, a proximal, a distal and a wedge fragment. After reduction there is some contact between the proximal and distal fragments.

12B2 fractures may have a spiral wedge resulting from a twisting injury or a bending wedge resulting from a bending injury.

This fracture type is subdivided:

• 12B2(a) - Proximal 1/3
• 12B2(b) - Middle 1/3
• 12B2(c) - Distal 1/3

Wedge fractures are generally more unstable than simple fractures.

In fractures located in the proximal zone of the diaphysis (12B2(a)), note that the deltoid muscle predominates and may interfere with treatment.

In fractures located in the distal third of the humerus (12B2(c)), the radial nerve is at risk more even than in the other regions.

Fracture with spiral wedge

Fracture with bending wedge

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