Anatomic variation of the clavicle: A novel three-dimensional study.

Abstract

An understanding of the complex anatomy of the clavicle is helpful in the treatment of clavicular fractures. Using three-dimensional (3D) statistical shape analysis, the author presents a novel method to assess geometric morphology of the clavicle. Fifteen fresh frozen shoulder specimens were scanned using high-resolution computerized tomography (CT) but four were excluded from the study. A further 16 high-resolution CT scans of the clavicle were obtained by searching the hospital database. All 27 scans were reconstructed and subsequently imported into and analyzed using a specifically developed statistical software package. Using statistical shape analysis, geometric parameters were then measured. Both gender as well as side specific geometric morphology were observed. Clavicles in men were longer, wider, and thicker than in women. Right clavicles had a greater medial depth than left clavicles, especially in women. Clavicles in men had a greater lateral depth than in women. The sternal angle in women was larger than in men. Using 3D statistical shape analysis and applying it to the clavicle standardizes the study of its anatomy, rules out any variability, and calculates morphological parameters that are accurate, precise, and reproducible. This unique approach provides information that is useful not only to the clinician but also in the modification of current or design of future clavicle fixation devices. More importantly, from an anatomy standpoint, implementation of this novel approach in anatomical studies would eliminate intra- and interobserver variation and allow all studies to be standardized and thus more comparable.