Simple transverse fractures of the humeral shaft are classified as 12A3 fractures.
There are only two fragments, and the fracture plane is short and with <30° obliquity.
This fracture type is subdivided:
Typically, these fractures are located in the middle third of the humerus (12A3(b)).
In fractures located in the proximal zone of the diaphysis (12A3(a)), note that the deltoid muscle predominates and may interfere with treatment.
In fractures located in the distal third of the humerus (12A3(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.