- Discussion:
- anatomic variations: of tendons in 1st extensor compartment;
- APL & EPB tendons may occupy separate canals, or lie together in one osseofibrous canal;
- commonly there is one EPB and multiple APL;
- there is separation of first extensor compartment more often in pts w/ DeQuervain's tenosynovitis than in those w/o condition;
- Anatomic Snuff Box:
- lies just dorsal and distal to the radial stylid process;
- radial border of snuff box is composed of APL & EPB which pass over the radial styloid process and etch a small groove on its lateral aspect; both travel through Tunnel I;
- ulnar border of snuff box is EPL tendon and floor of scaphoid bone;
- occasionally deep branch of radial artery is palpable where it crosses the scaphoid bone;
- termainal branches of the superficial radial nerve are also palpable where they cross the EPL tendon