import { HighYieldBox, ExamCheatSheet, Tabs, Tab, ComparisonTable, VivaScenario, ContentSection, SpecialTestCard , MedicalImage} from '@/components/content' # Wrist Carpal Instability Examination Carpal instability examination requires understanding the complex carpal ligament anatomy and different instability patterns. Examiners expect you to perform Watson's test correctly, understand the difference between DISI and VISI patterns, and assess the DRUJ systematically. ## Quick Reference One-Pager ## Anatomy and Instability Patterns **Intrinsic Ligaments (Between Carpal Bones):** - **Scapholunate (SL) ligament**: Strongest dorsally, prevents scaphoid flexion - **Lunotriquetral (LT) ligament**: Prevents lunate extension **Extrinsic Ligaments (Radius/Ulna to Carpus):** - Volar: Radioscaphocapitate, long radiolunate, short radiolunate - Dorsal: Radiotriquetral (dorsal radiocarpal) **Carpal Rows:** - Proximal: Scaphoid, lunate, triquetrum (pisiform) - Distal: Trapezium, trapezoid, capitate, hamate - Scaphoid spans both rows (link bone) **DISI vs VISI Patterns:** **DISI (Dorsal Intercalated Segment Instability):** - Lunate dorsiflexed (tilted dorsally greater than 15°) - Scapholunate angle greater than 70° (normal 30-60°) - Caused by SL ligament injury (scaphoid flexes, lunate extends) **VISI (Volar Intercalated Segment Instability):** - Lunate palmarflexed - Scapholunate angle less than 30° - Caused by LT ligament injury (less common) ## Clinical Presentation **Scapholunate Instability:** - Fall on outstretched hand (FOOSH) - Dorsal wrist pain (anatomical snuffbox deep) - Weakness with grip - Clicking with movement - "My wrist just doesn't feel right" **Lunotriquetral Instability:** - Ulnar-sided wrist pain - Pain with ulnar deviation - Clicking on the ulnar side **DRUJ Instability:** - Pain with forearm rotation - Weakness with pronation/supination - Prominent ulnar head - History of distal radius fracture ## Scapholunate Instability Tests **Watson's Test Interpretation:** - Clunk may occur in normal patients (hyperlaxity) - MUST compare with contralateral wrist - Pain with the maneuver is the key finding - Positive = painful clunk on AFFECTED side (not contralateral) - May need to repeat test several times ## Lunotriquetral Instability Tests ## DRUJ Instability Tests **DRUJ Testing Positions:** - **Pronation**: Tests dorsal radioulnar ligaments (tight) - **Supination**: Tests volar radioulnar ligaments (tight) - **Neutral**: Both ligaments contribute Test in all three positions and compare with contralateral side! ## Midcarpal Instability Tests **Types:** - **CIC (Capitolunate Instability Pattern)**: Most common - **CIND (Carpal Instability Nondissociative)**: Ligament laxity between rows **Clinical Features:** - "Catch-up clunk" with movement - Often bilateral (generalized ligamentous laxity) - Painful clicking with ulnar deviation - May improve with strengthening ## Imaging Correlation ## Differential Diagnosis ## Summary Presentation ## Examination Sequence 1. **Observation**: Swelling, deformity, prominence of ulnar head 2. **Palpation**: SL interval, LT interval, fovea, DRUJ 3. **Active ROM**: Flexion, extension, radial/ulnar deviation 4. **Grip Strength**: Compare with contralateral 5. **Watson's Test**: SL instability 6. **SL Ballottement**: SL integrity 7. **LT Tests**: Shuck test, shear test 8. **DRUJ Tests**: Ballottement, piano key 9. **Midcarpal Shift**: If suspected 10. **Neurovascular**: Complete examination ## Examiner Tips