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

The purpose of this study is to identify, 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 (3-D) surface model. Ten fresh-frozen cadaver wrists were used to dissect and identify the second through fifth CMC ligaments. The ligamentous attachments and whole bone surfaces were digitized three-dimensionally, and their areas were calculated. The attachments of each ligament were represented in a model in which their surfaces, as seen on computed tomography (CT), were overlaid with a digitized 3-D surface, and they were also visually demonstrated with a specific color on 3-D images of the bones. A total of 9 dorsal and 9 volar CMC ligaments and 1 CMC interosseous ligament were identified in the second through fifth CMC joints. An intra-articular ligament between the third and fourth metacarpals (MCs) and the capitate and hamate was also identified. In addition, 5 dorsal and 5 volar intermetacarpal ligaments and 3 intermetacarpal interosseous ligaments were also identified in the second through fifth intermetacarpal joints. A previously undescribed volar intermetacarpal ligament was found located between the third, fourth, and fifth MC bases. The anatomic 3-D attachment sites of the second through fifth CMC ligaments were visually depicted qualitatively, and their areas were quantified. This study has improved the knowledge and understanding of the normal anatomy and its impact on the mechanics of the second through fifth CMC joints. This 3-D information should facilitate the accurate assessment of radiographic images and the treatment of various injuries seen in the second through fifth CMC joints when performing ligament reconstruction, repair, osteochondral grafting, and arthroscopy. (author)