[Fracture of the coracoid process: its classification and pathomechanism].

Twenty-eight cases of fractures of the coracoid process were assessed regarding general characteristics, causes of injury, regions of contused wound, fracture types and complications. From the results of the assessment, the fractures were roughly divided into five types: type I; apical, type II; middle, type III; basal, type IV; intraarticular (including upper 1/3-1/4 of the glenoid cavity), and type V; others. Subtypes A and B were present in type III and IV. From the specifics of the contusions and complicated osseous-articular injuries around the shoulder, the mechanisms of injury in each type may be suggests as follows: type I and II; tractive force of attached muscular tendons, type III and IV; shearing force acting between the scapula shifting inward due to blow from the lateral aspect of the shoulder and the clavicle countering this movement, and type V; unspecified. The main cause of fractures of the superior scapular margin was considered to be the tractive force of the superior transverse scapular ligament, because almost all cases of subtype A were complicated with them. For the benefit of the clinical use, they should be classified into two groups: group A; without loss of connection between scapula and clavicle (mainly types I and II), and group B; with loss of the same (majority of types III and IV).