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