Nerve injuries are common and most of them are repaired surgically. However, because few nerve injuries are identical and the methods of testing outcome are rudimentary, there is no clear picture of the natural history of different types of nerve injury and no clear information to predict how they should be managed. This study will use carefully selected models of major types of nerve injury and follow them up after surgical repair. These researchers have developed new electrophysiological tests which will allow them to find out more details about the outcome of the repair. This will be used to predict the management and outcome of more diverse nerve injuries in the future.