Osseous and ligamentous scaphoid anatomy: Part II. Evaluation of ligament morphology using three-dimensional anatomical imaging.

PURPOSE: There are many controversies in the literature regarding the morphology of the scaphoid ligaments. The aim of this study was to provide a more accurate description by quantitatively describing the 3-dimensional, geometrical aspects of the scaphoid ligaments and their attachments, using cryomicrotome images of cadaveric wrists.

METHODS: Eight fresh-frozen human cadaver wrists were examined with computed tomography (CT) and an imaging cryomicrotome. A series of 2-dimensional cryoimages created a 3-dimensional anatomical data set of each test specimen. Detection of ligaments and their surface areas was performed by manually marking the course and attachment points for each ligament, using dedicated visualization software. The 3-dimensional bone surfaces were segmented from the acquired CT images and incorporated in the 3-dimensional anatomical data set of the same anatomical specimen to facilitate the detection procedure. The results of the morphological parameters and attachment areas of the scaphoid ligaments are described 3-dimensionally.

RESULTS: The mean size of the whole scaphoid surface was 1503 ± 17 mm(2), and the mean size of all ligament attachments on the scaphoid was 131 ± 14 mm(2); thus, ligament attachments consist of 9% ± 0.9% of the total scaphoid surface area. Based on the data, a 3-dimensional representation of the wrist was created to present the scaphoid ligament attachment areas and paths. The dorsal intercarpal ligament had the most individual variability between specimens in attachments.

CONCLUSIONS: The quantitative results were almost completely consistent with the findings of previous reports. The only inconsistency in ligament morphology regarded the scaphocapitate ligament, which in this study was found to be the thickest ligament attached to the scaphoid.

CLINICAL RELEVANCE: The results of this study improve our knowledge of scaphoid ligament anatomy, as they corroborate previous findings. This is important for carpal surgery and will pave the way to a better understanding of the biomechanics involved in destabilization of wrist fractures.