Ulnar Piano Key Sign
“Piano key sign: The ulnar head sits in a dorsal position. Like pressing a piano key, applying stress to the ulnar head causes substantial translation to volar (28,29). This test has 66% sensitivity and 68% specificity (29).”1
“The piano key test evaluates the stability of the ulnomeniscotriquetral joint. The clinician firmly stabilizes the distal radius with one hand and grasps the head of the ulna between the thumb and the index finger of the other hand. The ulnar head is depressed in an anterior direction (as in depressing a key on a piano) (Fig. 18-58). The test is positive for a TFCC tear or triquetral instability if there is excessive movement in an anterior (palmar) direction or if upon release of the ulna, the bone springs back into its high posterior (dorsal) position.”2