Three-dimensional analysis of the ligamentous attachments of the second through fifth carpometacarpal joints

The purpose of this study is to clarify, measure, and show the anatomic locations and areas of specific ligamentous attachments and paths of the second through fifth carpometacarpal (CMC) joints on a three-dimensional (3D) surface model. Ten fresh-frozen cadaver wrists were used to dissect and identify the second through fifth CMC ligaments. Their ligamentous attachments and whole bone surfaces were digitized three-dimensionally and their areas calculated. The attachments of each ligament were represented in a model combining CT surfaces overlaid by a digitized 3D surface, and were also visually demonstrated with a specific color on 3D images of the bones. Nine dorsal and 11 palmar CMC ligaments and one CMC interosseous ligament were identified in the second through fifth CMC joints. An intra-articular ligament between the third metacarpal (MC), the fourth MC, capitate, and hamate was also identified. Five dorsal and five palmar intermetacarpal ligaments and three intermetacarpal interosseous ligaments were also identified in the second through fifth intermetacarpal joints. A previously undescribed palmar intermetacarpal ligament was located between the third, fourth, and fifth MC bases. The anatomic 3D attachment sites of the second through fifth CMC ligaments were visually depicted qualitatively, and their areas quantified. This 3D information will not only afford a better understanding of the anatomy and mechanics of the second through fifth CMC joints, but will also assist in the assessment of radiographic images and treatment of various injuries.