Abductor

Pollicis

Longus

Extensor

Pollicis

Extensor

Carpi

Radialis

Longus

Extensor

Carpi

Radialis

Brevis

Extensor

Digitorum

Extensor

Digiti

Minimi

Extensor

Carpi

Ulnaris

Palmer classification for triangular fibrocartilage complex abnormalities

Class 1: Traumatic

     •     A - central perforation

     •     B - ulnar avulsion with or without distal ulnar fracture

     •     C - distal avulsion

     •     D - radial avulsion with or without sigmoid notch fracture

Class 2: Degenerative (ulnocarpal abutment syndrome) stage

     •     A - TFCC wear

     •     B - TFCC wear with lunate and/or ulnar chondromalacia

     •     C - TFCC perforation with lunate and/or ulnar chondromalacia

     •     D - TFCC perforation with lunate and/or ulnar chondromalacia and LT ligament perforation

     •     E - TFCC perforation with lunate and/or ulnar chondromalacia, LT ligament perforation, and ulnocarpal arthritis