- Anatomy:
- extensor tunnel I
- origin:
- posterior side at the distal end of the body of both the ulna and radius near their middle;
- insertion:
- posterior surface of the base of the proximal phalanx of thumb;
- action:
- extends proximal phalanx of the thumb; continued action extends and assists abduction of the 1st metacarpal;
- synergists: APL, EPL;
- nerve:: PIN branch of deep radial nerve, C6, C7;
- Discussion:
- annular ligament that restrains abductor pollicis longus & EPB over
radius is directly over radial tubercle;
- this area may be involved in DeQuervain's tenosynovitis
A simplified technique to correct hyperextension deformity of the metacarpophalangeal joint of the thumb.