Scratch Collapse Test: a new clinical test for peripheral nerve compression.

A 70-year-old woman presented left hand neuropathic pain and nocturnal paresthetic brachialgia. The neurological examination was unremarkable except for positive Scratch Collapse Test (SCT) suggesting left Carpal Tunnel Syndrome (CTS) (Figure). Subsequent electromyographic evaluation was consistent with left CTS. The SCT is a new clinical maneuver for peripheral nerve compression diagnosis that has greater sensitivity than both Tinel’s test and the flexion/nerve compression test for the median and ulnar nerves, respectively. It is believed that a silent period following cutaneous stimuli over the compressed nerve briefly inhibits external shoulder rotation, thus producing the sign which can be indefinitely repeated.