| Wrist Planes of Motion |
- Joints involves
- radiocarpal (accounts for two thirds of flexion-extension arc and part of ulnar deviation arc)
- intercarpal (accounts for one third of flexion-extension arc and most of radial deviation arc)
- Normal and function motion
- flexion (65 normal, 10 functional)
- 66% radiocarpal, 33% intercarpal
- extension (55, 35)
- 66% radiocarpal, 33% intercarpal
- radial deviation (15, 10)
- ulnar deviation (35, 15)
- 50% radiocarpal, 50% intercarpal
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| Wrist Biomechanics |
- Column Concept:
- Model of 3 biomechanic columns proposed by Taleisnik:
- lateral column
- scaphoid is center of motion and function is mobile
- central column
- distal carpal row and lunate (link of columns) and motion is flexion/extension
- medial column
- triquetrum is center and motion is rotation
- Link System
- Model of 3 links in a chain proposed by Gilford:
- radius-lunate-capitate
- links
- head of capitate acts as center of rotation
- proximal row (lunate) acts as a unit and is an intercalated segment with no direct tendon attachments
- distal row functions as unit
- function
- allows efficient motion with less motion required for each link but with compromise of stability
- strong volar ligament and the scaphoid which crosses links enhace stability
- resting forces/radial deviation push scaphoid into flexion (triquetrum into extension)
- ulnar deviation push scaphoid into extension
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| Volar Ligaments |
 Radioscaphoid
- functions primarily as a neurovascular conduit.
- Radioscaphocapitate
- at risk for injury with excessively large radial styloid
- Radioscapholunate
- Radiolunate (short and long)
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| Dorsal ligaments |
 Radiotriquetral
- must also be disrupted for VISI deformity to form (in combination with rupture of lunotriquetral interosseous ligament rupture)
- Radiolunate
- Radioscaphoid
- Dorsal intercarpal
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| Interosseous ligaments |
- Proximal row
- lunotriquetral interosseous ligament
- must also be disrupted for VISI deformity to form (in combination with rupture of dorsal radiotriquetral rupture)
- scapholunate interosseous ligament
- Distal row
- trapeziotrapezoid interosseous ligament
- trapeziocapitate interosseous ligament
- capitohamate interosseous ligament
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| Midcarpal ligaments |
- Palmar midcarpal
- scaphotrapezial trapezoid
- scaphocapitate
- triquetralcapitate
- triquetralhamate
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| Ulnocarpal ligaments |
- Ulnocapitate
- Ulnolunate
- Ulnotriquetral
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