12-A1 Simple fracture, spiral
A1 fractures of the humeral shaft are simple fractures with a spiral fracture line.
In A1 fractures located in the proximal zone of the diaphysis (12-A1.1), note that the deltoid muscle predominates and may interfere with treatment.
In fractures located in the distal third of the humerus (12-A1.3), the radial nerve is at risk more even than in the other regions.
Image taken from Orozco R, et al. (1998) Atlas of Internal Fixation. Used with kind permission.