Aspects of coracoacromial ligament anatomy of interest to the arthroscopic surgeon.

Examination was performed on 100 cadaveric specimens to demonstrate the anatomy of the coracoacromial (C-A) ligament. In a substantial number (34 specimens), the bipartite nature of the ligament and the breadth of its insertions were considerably more pronounced than usually perceived through the arthroscope. Supplementing the cadaveric material, 300 dry bone scapulae were examined from museum specimens of older persons. These demonstrated various degrees of transformation of the C-A ligament into bone (enthesopathy) at its acromial insertion. Variations in the patterns of these enthesopathic transformations corresponded to variations in the patterns seen in the cadaveric material. This variability is of practical importance in a variety of operative procedures. Additionally, the relationship between the acromial insertion of the C-A ligament and the overlying deltoid muscle was examined. An understanding of this relationship is crucial in avoiding complications when operating in this area.