Anatomy of the Clavicle and Coracoid Process for Reconstruction of the Coracoclavicular Ligaments

Abstract

Background Recently acromioclavicular joint reconstruction techniques have focused on anatomic restoration of the coracoclavicular (CC) ligaments. Such techniques involve creating bone tunnels in the distal clavicle and coracoid. Purpose To define the anatomy of the human clavicle and coracoid process of the scapula, in order to guide surgeons in reconstructing the CC ligaments. Study Design Descriptive laboratory study. Methods One hundred twenty (60 paired) cadaveric clavicles and corresponding scapulae (mean age ± and standard deviation, 48.3 ± 16.6 years) devoid of soft tissue were analyzed (dry osteology). Differences related to race and sex were recorded. Nineteen fresh-frozen cadaveric clavicles with intact CC ligaments were measured as well (fresh anatomic). Results The mean clavicle length was 149 ± 9.1 mm. In the dry osteology group, the distance from the lateral edge of the clavicle to the medial edge of the conoid tuberosity in male and female specimens was 47.2 ± 4.6 mm and 42.8 ± 5.6 mm, respectively (P = .006). The distance to the center of the trapezoid tuberosity was 25.4 ± 3.7 mm in males and 22.9 ± 3.7 mm in females (P = .04). The ratio of the distance to the medial edge of the conoid tuberosity divided by clavicle length was 0.31 in males and females. This ratio for the trapezoid was 0.17 in both sexes. The mean coracoid length was 45.2 ± 4.1 mm. The mean width and height of the coracoid process were 24.9 ± 2.5 mm and 11.9 ± 1.8 mm, respectively. No interracial differences in measurements were observed. In the fresh anatomic samples, the ratio of the distance to the conoid center to clavicle length was 0.24. This ratio for the trapezoid was 0.17. Conclusions While absolute differences in the origin of the CC ligaments exist between men and women, the ratio of these origins to total clavicle length is constant. Clinical Relevance Clavicle length can be obtained intraoperatively. These findings allow the surgeon to predict the origin of the conoid and trapezoid ligaments accurately and to correctly create bone tunnels to reconstruct the anatomy of the CC complex.