Extensor compartments of the wrist
The extensor tendons at the level of the wrist are divided into six extensor compartments that are designated by Roman numerals from lateral to medial :
- I: extensor pollicis brevis, abductor pollicis longus
- II: extensor carpi radialis longus, extensor carpi radialis brevis
- III: extensor pollicis longus
- compartments 2 and 3 are divided by Lister's tubercle of the distal radius
- IV: extensor digitorum, extensor indicis
- V: extensor digiti minimi
- VI: extensor carpi ulnaris
- runs in the groove of the ulnar head
