RESUMO
INTRODUCTION: The sternoclavicular joint is of clinical importance. However, there is scant information in the literature regarding one ligament of this area, the costoclavicular ligament (CCL). MATERIAL AND METHODS: In order to further elucidate this structure, 10 adult formalin-fixed cadavers (17 sides) underwent dissection of the CCL. Once the CCL was identified, measurements were made of its dimensions and observations made of its anatomy. Next, ranges of motion were performed of the upper extremity and the CCL observed for tension or laxity. RESULTS: Of the 17 sternoclavicular regions examined 16 (94%) were found to possess a CCL. The average medial and lateral lengths, width and thickness were 1, 2, 1.2, 0.340 cm, respectively. The width of the CCL was statistically smaller in women that in men. The majority of ligaments were single structures traveling from the inferior surface of the medial clavicle just lateral and sometimes-fused (12.5%) to the lateral edge of the sternoclavicular joint. These fibers then terminated on the medial end of the first rib and first costal cartilage (75%) or exclusively onto the first costal cartilage (25%). Most ligaments were single and not composed of two parts. Arm abduction resulted in tautness of the ligament and increased as the degree of abduction increased. Internal rotation of the arm translated into medial shift of the clavicle, raising the clavicle away from the first rib creating tension on the CCL. Moderate degrees of external rotation were required before the CCL became taut and even began to pull the first rib laterally. Small amounts of protraction and retraction of the scapula both put the CCL under tension. CONCLUSIONS: The CCL is a constant structure found just lateral to the sternoclavicular joint. This ligament was a single band in the majority of our specimens and limited most ranges of motion of the proximal upper limb thus stabilizing the sternoclavicular region.