Riche-Cannieu connection in median nerve injuries

The Riche-Cannieu connection between the deep branch of the ulnar nerve and the recurrent motor branch of the median nerve was first noted in hand dissections almost 100 years ago. It was then considered rare and unimportant. Electrophysiologists have recently shown that this connection occurs in a large proportion of normal volunteers and accounts for a variable proportion of motor response in the thenar musculature. This report describes two cases of median nerve injuries with intact thenar function and postulates that this anomalous clinical presentation is due to the Riche-Cannieu connection. The unusual clinical situations emphasize the need for careful evaluation of nerve injuries.