STUDY OF STRUCTURE OF CORACOCLAVICULAR LIGAMENT TO CORRELATE ITS’ ROLE IN WEIGHT TRANSMISSION

Abstract

AIMS AND OBJECTIVES: The present study was undertaken to correlate structure of coracoclavicular ligament with its’ role in transmission of weight from upper limb to the axial skeleton.The study was done for the morphology of coracoclavicular ligament (parts, attachments, direction of fibers and thickness) and to look for any variation in morphology of the ligament.

MATERIAL AND METHOD: Sixty coracoclavicular ligaments were studied on right and left sides of thirty cadavers donated at the Anatomy department, Pramukhswami Medical College, Karamsad. Coracoclavicular ligament was studied for morphology of its conoid and trapezoid parts, attachments of both and variations.

RESULT: Anteriorly trapezoid part of the coracoclavicular ligament overlapped the lateral half of conoid part of. (Plate- 1). In all 60 cases, trapezoid fibers were directed upwards and laterally and it was quadrangular in shape. This component was thinner than conoid part. As compared to trapezoid part, conoid part was thick laterally and inferiorly. The fibers of conoid part were directed upwards and medially. A vertical slit like gap was observed between these two parts. In posterior view (Plate- 4), conoid part showed continuity with trapezoid part. The line of attachment of the coracoclavicular ligament on coracoid process was inverted L shaped (Plate-2). On clavicle the line of attachment was delta shaped. In four specimens, the trapezoid part of coracoclavicular ligament was grossly giving appearance of muscular tissue (Plate-5). Out of 60 specimens, in 20 specimens, the coracoclavicular ligament was continuous with the suprascapular ligament (Plate- 6).

In four cases, from inferior most attachment of coracoclavicular ligament at the root of coracoid process, an extra band was observed. (Plate-7). In two cases, extra band of coracoclavicular ligament was found anteriorly (Plate- 8).

CONCLUSION: Conoid ligament was much thicker as compared to trapezoid ligament which indicates that, the conoid ligament was more important in weight transmission and for providing stability to acromioclavicular joint. The fibers of conoid ligament were directed upwards and medially. These suggest that, the conoid ligament transmits weight of upper limb upwards and medially from coracoid process to clavicle. Postero-medially, the fibers of conoid ligament were twisted, these twisted fibers suggest the role of the ligament in movements of pectoral girdle and in providing stability to acromioclavicular joint. Continuity of conoid part with suprascapular ligament enhances the thickness of the supra scapular ligament and may reduce the size of the suprascapular notch. This may cause entrapment of suprascapular nerve and vessels. Variations were more commonly related with conoid ligament than trapezoid ligament. Among these variations the continuity of coracoclavicular ligament with suprascapular ligament was most common. In present study, the age of cadavers range between 50-89 years. There was not a single incidence of ossification of the ligament or presence of cartilaginous nodule within this ligament. Similarly, coracoclavicular joint was not found in any of them. Therefore, it could be deduced that coracoclavicular joint could be found at any age and occurrence of this joint was not an effect of the aging process.