Hand opening in individuals with stroke is often impaired by abnormal wrist and finger flexor activity. Emerging electrical nerve block technologies could reduce this abnormal flexor activation, but the impact of such a reduction on hand opening has not been fully studied. In this study, we induced a complete block of the median and ulnar nerve in 9 individuals with stroke using local anesthesia as a proxy. Volitional and functional-electrical-stimulation-driven (FES) hand opening was evaluated before and after block, both with the arm supported (Unloaded) and while lifting the weight of the limb (Loaded), using a new metric called Hand Hexagon Area. Linear Mixed Effects Regression models showed that hand opening under Loaded conditions may improve between 9–11% following block. Our results suggest that while extensor weakness and “claw hand” can limit individual outcomes, nerve block interventions could still address prior shortcomings of FES interventions.