Scapholunate Instability, Ulnar-Sided Wrist Pain and the TFCC

Ian explains the scapholunate stress test, often called Watson's test: pressure on the scaphoid tubercle while moving from ulnar to radial deviation. A blocked scaphoid with dorsal pain suggests injury with the ligament intact, while free movement suggests a complete tear. Dynamic instability shows a gap only with a clenched fist or ulnar deviation, while static instability shows it in neutral. A grip dynamometer and a weight-bearing scale test load the wrist in open and closed chain. A 2017 study by Nance and colleagues looked at loaded wrist extension pain. In the dorsal group, 84% had an identifiable cause, mostly occult ganglion cysts, while in the ulnar group only 12% did. This is why the ulnar wrist is called the black box, and functional tests help where imaging does not. The TFCC acts like a meniscus and takes more torsion when external forces such as a racket increase radiocarpal motion. Wipers train wrist control against forearm rotation, and push-offs load the wrist in open-packed positions to build stability.