The coracoid process serves as the attachment site for many structures, including the conjoint tendon of the coracobrachialis and the short bead of the biceps, the pectoralis minor muscle, the coracoacromial ligament (CAL), the coracoclavicular (CC) ligaments, and the coracohumeral ligament. Given the close proximity and intimate relations of these important structures, a precise, quantitative understanding of their relations is crucial to the successful surgical management of pathology in this region. For example, the CAL has been formerly described as a flat triangular band extending from the coracoid process to the acromion. Currently, the literature includes reports of the CAL origin from the apex of the acromion, from the medial or inferior border, or even from the broader extent of the inferior surface of the acromion. The precise anatomic location of the CAL is important to consider in the setting of many procedures including acromioplasty and capsular repair in the Latarjet procedure. Furthermore, understanding the intricate anatomy of the CAL may aid surgeons to anatomically repair or reconstruct this structure because the disruption of the coracoacromial arc has been associated with superior migration of the humeral head.

Modern techniques in shoulder surgery emphasize the importance of detailed knowledge of the native anatomy to avoid iatrogenic injury to important anatomical structures. In the Latarjet procedure, the coracoid process is osteotomized and transferred along with the conjoint tendon of the coracobrachialis and short head of the biceps tendon to the anterior glenoid rim to treat glenoid bone loss and restore glenohumeral joint stability. Limited literature exists regarding the anatomical gender differences pertinent to performing an osteotomy of the coracoid. In addition, in cases of acromioclavicular (AC) joint dislocation, in which the CC ligaments are torn, their original attachments may be difficult to identify. In these cases, other landmarks should be used to guide anatomical reconstruction. Rios suggested that the medial edge of the bony tunnels could be calculated as percentages of the clavicular length (as measured from the lateral border of the clavicle). Thus, the tunnels for the reconstructed conoid and trapezoid ligaments should be created on the superior clavicle, at a point representing 30% and 17% of the clavicle length, respectively. In addition, Salzmann found that the CC ligament footprints could be reproducibly predicted with respect to the medial border and the “precipice” of the coracoid process. These 2 studies provide baseline data that can be used to guide anatomic reconstruction of the CC ligaments.

A limited number of reports have documented the qualitative anatomy of the structures attaching to the coracoid process. Likewise, limited quantitative data exist that characterize the intricate anatomy of this region. Thus, the purposes of this study were to perform a quantitative anatomic evaluation of (1) the coracoid process and more specifically the attachment sites of the conjoint tendon, the pectoralis minor, the CAL, and the CC ligaments in relation to pertinent osseous and soft tissue landmarks; (2) the CC ligaments’ attachments on the clavicle; and (3) the CAL attachment on acromion in relation to surgically relevant anatomic landmarks to assist in planning of the Latarjet procedure, AC joint reconstructions, and CAL resections to avoid iatrogenic injury to surrounding structures. We hypothesized that consistent attachment areas and distances to relevant surgical landmarks would be identified.

Full Article: Quantitative Assessment of the Coracoacromial and the Coracoclavicular Ligaments With 3-Dimensional Mapping of the Coracoid Process Anatomy: A Cadaveric Study of Surgically Relevant Structures