Functional aspects of the coracoclavicular space

Abstract

The coracoclavicular joint has been described as an articulation found inconstantly between the coracoid process and clavicle. We often observe a small space bordered by the fascia which covers the anterior surface of the subclavius muscle and the coracoclavicular ligament. The aim of this study was to observe the space in detail and to discuss the functional role of the coracoclavicular joint. Sixteen shoulder girdles from eight Japanese cadavers were used in this study. The scapula, clavicle, and anterior half of the first rib were extracted en bloc together with the subclavius muscle and the surrounding fascia. After observing the motion of the scapula and clavicle, we investigated macroscopically the attachments of the coracoclavicular ligaments and the subclavius muscle, and the extension of the fascia. The fascia divided laterally into two sheets: the anterior sheet attached to the trapezoid ligament and the posterior to the conoid ligament. Among the two sheets, the coracoclavicular ligaments, coracoid process, and clavicle, a small space was observed. This small space can be recognized as a part of the coracoclavicular joint. When manually moving the inferior angle of the scapula with the sternal end of the clavicle fixed, we observed that the clavicle collided with the trapezoid ligament on the superior surface of the coracoid process within the space and that the scapular motion was restricted by this collision. The coracoclavicular joint could be much more recognizable than in previous papers and play an important role in the normal function of the shoulder joint. Basic science study.