Traumatic instability of the wrist: diagnosis, classification, and pathomechanics.

摘要: The scaphoid is a mechanical link that stabilizes the intercarpal joint during motions of wrist. Without this stability proximal carpal row acts as an unsupported intercalated in three-link system and zigzag collapse occurs with axial loading. A deformity dorsiflexion lunate within linkage (dorsiflexion instability) commonly after fracture scapholunate dissociation. When dissociation assumes vertical position, is, angle formed by longitudinal axes approaches right angle. Rupture distal attachments palmar radiocarpal ligament appears to induce It therefore concluded ligamentous injury along probably necessary if instability develop. Palmar flexion characterized wrist be associated ulnar displacement carpus seen rheumatoid arthritis or loss end ulna. This position may normal small percentage patients. direction related location pressure head capitate against concave surface lunate, whether dorsal plane radiolunate fulcrum on convex lunate. also oblique path motion (rotation sliding) radial deviation intimately controlled geometric configuration bones resultant forces carpus. These are determined strength, direction, leverage musculotendinous units, which cross joints complex.