The ulnar collateral ligament of the wrist connects the ulnar styloid to the triquetrum and pisiform, providing ulnar-sided stability alongside the much larger TFCC. Ulnar styloid fractures at the base can disrupt the UCL and TFCC attachment, potentially producing DRUJ instability that requires assessment and repair. Isolated UCL wrist injuries are uncommon as the TFCC is usually the primary structural failure in ulnar-sided wrist injuries.
| Origin | Ulnar styloid process |
|---|---|
| Insertion | Pisiform and triquetrum |
| Actions | Limits radial deviation; provides ulnar-sided wrist stability alongside the TFCC |
|---|
Ulnar styloid base fractures that involve the TFCC and UCL attachment (distinct from the tip fractures that are biomechanically irrelevant) require assessment for associated DRUJ instability. Persistent DRUJ instability after distal radius fracture fixation from UCL and TFCC disruption at the ulnar styloid may require styloid fixation or TFCC repair to restore stability.
Ulnar styloid base avulsion with UCL and TFCC attachment disruption producing DRUJ instability requiring styloid fixation or TFCC repair.
