We had an interesting case last week of a lady with a deep motor branch ulnar neuropathy from a pretty severe 5th metacarpal fx. Ulnar CMAP to the ADM was normal (didn't compare her other side though) and to the FDI the amplitude was less than 1 (0.4? I'd have to look again). Ulnar SNAP was normal. My attending was able to get a low amplitude DUC despite the surgical scar. She couldn't adduct her 2nd and third fingers and had 3/5 finger ADM/FDI. Needle of her FDI>ADM showed denervation...
Deep Motor Branch Ulnar Neuropathy
Deep Motor Branch Ulnar Neuropathy