Morphometric Analysis of Clavicle and Its Medullary Canal: A Computed Tomographic Study

Intramedullary fixation is one of the common methods of treating clavicle fractures. Morphometric data of the clavicle and its medullary canal will help design a better device and surgical technique. Morphometric studies on clavicle are sparse; hence, this study.

A 3-D reconstruction of 64 clavicles of 32 patients was done from computed tomography (CT) scan data of thorax obtained for the diagnostic workup of unrelated disease. The various dimensions of the clavicle and its medullary canal were measured. The narrowest part, point of change of direction of the medullary canal, curvatures of the clavicle, the position of the coracoid process, and the relation of these features to eight equally divided segments of clavicle were noted.

The average length of the clavicle was 142.5 mm. The average height and width of the narrowest part of the medullary canal were 2.4 mm and 2.5 mm, respectively, corresponding to segment 5 (S5) in more than half of the clavicles. The change of direction of the medullary canal and the medial edge of the coracoid process were corresponding to segment 6 (S6) in the majority of the clavicles.

This computed tomographic study provides morphometric data of the clavicle applicable to intramedullary fixation of clavicle fractures. In the studied population, the clavicles were shorter, more curved, and had medullary canal dimensions less than 2.5 mm at the narrowest part. This may pose difficulties in intramedullary fixation. The coracoid process was a reliable anatomical landmark.