Multifragmentary fractures of the humeral shaft with an intact segment are classified as 12C2 fractures.
There are two main fragments, a proximal and a distal. After reduction there is no contact between the proximal and distal fragments. There is also an intact segment.
This fracture type is subdivided:
12C2 fractures are rare.
In fractures located in the proximal zone of the diaphysis (12C2(a)), note that the deltoid muscle predominates and may interfere with treatment.
In fractures located in the distal third of the humerus (12C2(c)), 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.