Anatomical relationship between the morphology of the styloid process of the ulna and the attachment of the radioulnar ligaments

• Published in: Journal of anatomy 2020-12, Vol.237 (6), p.1032-1039
• Main Authors: Horiuchi, Saya, Nimura, Akimoto, Tsutsumi, Masahiro, Suzuki, Shiro, Fujita, Koji, Nozaki, Taiki, Akita, Keiichi
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Bone imaging; Cadaver; Cadavers; Computed tomography; Cortical bone; dorsal; Female; Humans; ligament; Ligaments; Ligaments, Articular - anatomy & histology; Ligaments, Articular - diagnostic imaging; Magnetic Resonance Imaging; Male; Mechanical loading; Middle Aged; Morphology; Original Paper; Original Papers; palmar; radius; triangular fibrocartilage complex; Ulna; Ulna - anatomy & histology; Ulna - diagnostic imaging; wrist; Wrist Joint - anatomy & histology; Wrist Joint - diagnostic imaging; X-Ray Microtomography
• ISSN: 0021-8782; 1469-7580
• DOI: 10.1111/joa.13275

The radioulnar ligaments are the major stabilizers of the distal radioulnar joint under dynamic loading; however, anatomical detail regarding their attachment on the middle and distal thirds of the styloid process of the ulna remains unclear. Because previous anatomical studies included only old cadavers, their anatomical findings might not reflect the morphological features of younger and healthy specimens. This study investigated the anatomical features of the distal ulna, particularly the styloid process, to determine the attachment of the radioulnar ligaments to the styloid process and verified their direction and attachment to the styloid process in younger and healthy donors using magnetic resonance imaging (MRI). We investigated the morphological features of the distal ulna of 12 cadaveric wrists using micro‐computed tomography (micro‐CT). We also visualized and measured the distribution of the cortical bone thickness. We histologically analyzed three specimens in the axial plane and macroscopically analyzed seven specimens to examine the attachment of the radioulnar ligaments to the styloid process. In addition, we evaluated five wrists from living volunteers using 3.0 Tesla MRI. The distal ulna has a ridge on the dorsoradial aspect of the styloid process that corresponds to the attachment of the radioulnar ligaments. Micro‐CT images after data processing revealed that the cortical thickness of the dorsoradial quadrant was thicker than that of the other quadrant at the proximal slice of the styloid process (p