Topographic Anatomy of Distal Radioulnar Ligament Insertion in the Distal Ulna

Abstract

Background: Insertion of the distal radioulnar ligaments onto the distal ulna is critical to provide translational stability and rotational guidance of the forearm. However, the topographic anatomy of the footprints of these ligaments and their relationships with morphometry of the distal ulna remain unclear. Purpose: We provide a detailed description of the anatomy and the relationships described above in a cadaveric study. Methods: Seventeen human distal ulnas attached by both the superficial and deep limbs of the distal radioulnar ligaments were scanned using micro-computed tomography and reconstructed 3 dimensionally. Results: The deep limbs have narrow marginal insertions just behind the pole of the distal ulna, but the width of the footprint was larger at the fovea than at the peripheral lesion. The superficial limb footprints were the circular and condensed shape. The center of the deep limb was radially distant from the base of the ulnar styloid by a mean of 2.00 ± 0.72 mm, and the distance was positively correlated with the width of the ulnar styloid ( r = .517, P = .030). The mean distance between the center of the ulnar head and the center of the fovea was 2.34 ± 0.62 mm. Conclusions: The deep limb has a narrow marginal insertion just behind the pole of the distal ulna, suggesting its role as the capsular ligament. The center of the fovea is located more radially from the ulnar styloid base. The data provide a better understanding of distal radioulnar ligament-related pathology to perform distal ulnar fixation or ligament repair to recover distal radioulnar joint stability.