A new method of electrodiagnosis during operations on the brachial plexus and peripheral nerve injuries. The value of motor nerve action potentials evoked by trans-skull motor area stimulation.

A method is described which records efferent motor nerve action potentials (MNAPs), evoked by trans-skull motor area stimulation, directly from a nerve root or peripheral nerve fibres during operation. The records of MNAPs from the root show whether function of the anterior root is intact and its continuity retained. When recorded from the proximal stump of a divided nerve at the wrist the motor funiculus can be identified, enabling funicular nerve suture to be carried out more easily.