What ligament connects the scaphoid bone?

Ligament Connections of the Scaphoid Bone

The scaphoid bone is primarily connected by the scapholunate interosseous ligament, which is the most important stabilizer of the scapholunate articulation, connecting the proximal pole of the scaphoid with the lunate in a distally concave semicircular fashion. 1, 2

Primary Ligamentous Connections

• The scaphoid has three main directional ligamentous connections: proximally toward the distal radius, distally toward the distal carpal row, and ulnarly toward the adjacent lunate 1
• The scapholunate interosseous ligament is the primary stabilizer of the scapholunate articulation, with its disruption leading to significant scaphoid instability 2, 3
• The interosseous scapholunate ligament connects the proximal pole of the scaphoid with the lunate in a distally concave semicircular pattern 1

Secondary Stabilizing Ligaments

• The palmar radiocarpal ligament consists of three distinct fiber complexes, with the radiocapitate and deep radioscapholunate ligaments inserting on the scaphoid 1
• The radial collateral ligament courses to the distal pole of the scaphoid 1
• The dorsal radiocarpal ligament passes the proximal pole of the scaphoid without direct attachment but contributes to secondary stabilization 1, 2
• The dorsal intercarpal ligament spans from the scaphoid tubercle to the triquetrum across the midcarpal joint 1, 2
• Short ligaments extend between the distal pole of the scaphoid and the trapezium (palmarly, dorsally, and radially) and between the distal pole of the scaphoid and the trapezoid (palmarly and radially) 1

Clinical Significance in Imaging

• Scapholunate ligament tears can be detected through various imaging modalities, with CT arthrography having the highest sensitivity (nearly 100%), specificity, and accuracy 4, 5
• MRI (especially 3T) is commonly used with reported sensitivities of 65-89% for scapholunate ligament tears 4, 5
• In low-grade injuries, radiographs are usually normal, but scapholunate diastasis >4 mm and dorsal tilt of the lunate >10° suggests dorsal intercalated segmental instability 4

Biomechanical Importance

• Sequential sectioning of the scapholunate interosseous ligament followed by secondary stabilizers (dorsal radiocarpal, dorsal intercarpal, and scaphotrapeziotrapezoid ligaments) causes progressive scaphoid collapse into flexion, ulnar deviation, and pronation 3
• Following disruption of the dorsal portion of the scapholunate interosseous ligament, the scaphoid becomes significantly more flexed, ulnarly deviated, and pronated relative to the radius 3
• The lunate becomes more extended, supinated, and volarly translated when the scapholunate ligament is compromised 3

Common Controversies in Scaphoid Ligament Anatomy

• Variations in anatomic descriptions are mostly due to difficulty identifying individual interdigitating ligaments by macroscopic dissections and interindividual variability 6
• The most controversial scaphoid ligament attachments include the radial collateral ligament, dorsal radiocarpal ligament, dorsal intercarpal ligament, volar scaphotriquetral ligament, and scaphotrapezium-trapezoid ligament 6
• None of the scaphoid ligaments other than the scaphocapitate ligament have been described consistently in the literature 6