Medial oblique compression fracture of the coronoid process of the ulna.

The most widely recognized coronoid fractures have been described as occurring in the coronal plane according to the amount of process detached from the ulna. Over the last few years, we have recognized that the coronoid fracture is a much more complex injury than originally thought. This report calls attention to an oblique, medial compression fracture of the coronoid, a fracture so subtle as to be missed by routine assessment but sometimes associated with joint subluxation or dislocation. The currently accepted classification system based on a simple fracture pattern in the coronal plane may be too simplistic to characterize fractures of the coronoid fully.