Classification Description Notes
IIA Very proximal ulna and includes the coronoid process  
IIB Distal to the coronoid process at the junction of the ulna metaphysis and diaphysis  
IIC Ulna diaphysis  
IID Complex ulna fracture that extended

from the olecranon to the diaphysis




Jupiter JB, Leibovic SJ, Ribbans W, Wilk RM. The posterior Monteggia lesion. Journal of orthopaedic trauma. 1991;5(4):395-402.