The TFCC proper (triangular fibrocartilage disc) is the central fibrocartilage component of the TFCC complex, suspended between the distal radius and ulnar head. It transmits load from the ulnar carpus to the ulnar head and extends the radiocarpal articular surface medially. The deep fibres at the fovea — the primary DRUJ stabilisers — are the critical structure repaired in DRUJ instability (Palmer 1B tears). Central disc perforations (Palmer 1A) are associated with positive ulnar variance.
| Origin | Ulnar corner of the distal radius (sigmoid notch) |
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| Insertion | Ulnar styloid base and fovea of the ulnar head — the foveal attachment provides the primary DRUJ stability |
| Actions | Primary DRUJ stabiliser; extends the radiocarpal articular surface to the ulnar side; transmits 20% of wrist load through the ulnar column |
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Palmer classification of TFCC tears: Class 1 (traumatic) — 1A central perforation, 1B ulnar avulsion at the fovea, 1C distal avulsion, 1D radial avulsion. Class 2 (degenerative — from ulnar abutment). Foveal tears (1B) produce DRUJ instability and require arthroscopic or open foveal reinsertion. Central perforations (1A) causing pain are treated with arthroscopic debridement.
Ulnar TFCC avulsion at the fovea producing DRUJ instability managed with arthroscopic foveal reinsertion.
