- Anatomy:
- origin:
- small facet of ulnar side of the radius near its middle;
- on lateral side of dorsal surface on body of the ulna just below the insertion of
anconeus & interosseous membrane;
- tunnel: travels thru the
first extensor compartment;
- insertion:
- most often this tendon inserts onto the APB muscle or it inserts into the radial side of the base of the 1st metacarpal;
- action:
- functions as a wrist flexor and radial deviator;
- abducts and assists in flexion of the thumb carpmetacarpal;
- synergists: APB,
EPL;
- nerve:
PIN branch of deep radial nerve,
C6,
C7;
- Other Considerations:
- annular ligament that restrains abductor pollicis longus &
epb over radius is directly over the radial tubercle;
- this area may be involved in
DeQuervain's tenosynovitis;
- note that almost every APL will have accessory tendons;
