The Dorsal Scapholunate Ligament Complex: Anatomical Description and Correlation with Lunate Morphology

This anatomical study aimed to describe, quantify, and topographically correlate the insertions of the dorsal scapholunate complex (DSLC) components, specifically the dorsal scapholunate interosseous ligament (dSLIL), dorsal radiocarpal (DRC), dorsal intercarpal (DIC), and dorsal capsuloligamentous scapholunate septum (DCSS), with each other and in relation to lunate morphology (types I and II).

Twenty-seven cadaveric wrists (23 formalin fixed and 4 fresh frozen) were systematically dissected. Measurements of width and thickness for dSLIL, DRC, DIC, and DCSS insertions were performed using a 0.05-mm precision caliper. Lunate morphology was classified (Viegas type I or II). Statistical analysis included descriptive statistics, independent samples t tests or Mann-Whitney U tests for intergroup comparisons, and paired-sample tests for dSLIL insertion site differences.

DRC width at the lunate insertion was significantly greater in type II lunates compared to type I (P < .001, Cohen's d = -1.647). No other DSLC component measurements differed significantly between lunate types. The dSLIL showed no notably difference in dimensions between its scaphoid and lunate insertions. Topographically, the scaphoid apex was identified as a consistent insertion site for dSLIL and DIC, with the DCSS located anterior and slightly ulnar to it.

This study provides a detailed morphological characterization of the DSLC components and their topographical relationships. Key findings include a more robust DRC at the lunate insertion in type II lunates and consistent insertion patterns of dSLIL and DIC at the scaphoid apex.

The observed robustness of the DRC in type II lunates suggests a potential protective effect against dorsal intercalated segment instability collapse. The precise anatomical data regarding DSLC component insertions offer crucial guidance for improving arthroscopic diagnostic accuracy and refining surgical reconstruction techniques for scapholunate instability.