[Multiple abnormal innervation of the hand in one patient. Electrophysiological diagnosis]

Nerve anastomoses in the hand are deviations from the anatomical norm. They do not lead to illness, but still they are events related with electrodiagnostic difficulties and, due to their unexpected presentation, also with iatrogenesis in regional surgical interventions.

We report the neurophysiological study conducted on a 45-year-old female who was found to have Riche-Cannieu-type motor anastomosis between the median and ulnar branches in the palm of the hand, complete innervation of the 4th finger by the ulnar nerve and complete innervation by the superficial radial of the back of the hand.

Anatomical descriptions of abnormal innervations in the hand are frequent, especially of the sensory kind. They do not usually give rise to any problems, even when the communicating branch is injured, probably owing to the scant participation of axons that usually occurs in anastomosis. They are not difficult to recognise by means of electroneurography if we are aware of their different types and we have a good knowledge of the anatomical routes. This will enable us to develop accurate diagnostic protocols. Knowledge of these variants will prevent electrodiagnostic errors and surgical iatrogenic effects from occurring.