Coracoclavicular ligament attachment regions of the Chinese population: a quantitative anatomic study

It is reported that the coracoclavicular (CC) ligaments arise at a constant region, which is proportional to the size of the clavicle and the coracoid process. However, all cadavers in those studies were from whites or African-Americans. The aim of this study was to evaluate dimension and orientation of CC footprints in Chinese cadavers and to determine whether race-dependent differences in these measurements exist. A total of 172 shoulders from 87 Chinese cadavers were used in this study, and the CC ligaments including the coracoid and the lateral clavicle were exposed. After measurement of the length of the CC ligaments, the ligaments were dissected and the insertion sites as well as the footprint centers were identified and marked. Each CC insertion dimension and its distance to the bony landmarks were recorded. Ratios representing the distance from the clavicular landmarks to each footprint center divided by clavicular length and clavicular width were calculated. These ratios were calculated for the coracoid process as well. The mean length of the clavicle and the coracoid process was 139.9 ± 9.4 and 40.5 ± 4.0 mm. The distance from the lateral edge of the clavicle to the conoidal center and to the trapezoidal center was 35.7 ± 3.4 and 21.8 ± 2.7 mm, respectively. The distance from the tip of the coracoid to the conoidal center and to the trapezoidal center was 35.1 ± 3.2 and 29.7 ± 2.9 mm, respectively. The ratios of the distance to the conoidal center and to the trapezoidal center divided by clavicular length and coracoidal length were 25.5, 15.6, 86.8 and 73.4 %, respectively. While absolute differences in the origin of the CC ligaments exist between different races, the ratio of these origins to the size of the clavicle and the coracoid process is constant.