Anomalous reinnervation as a sequel to obstetric brachial plexus palsy.

In 3 patients with sequelae of brachial plexus birth injury we observed associated movements and also synchronous motor unit potentials and motor axo-axonic reflexes between different muscles, sometimes with antagonist function. To explain these synkineses is necessary to assume that there is simultaneous innervation by the same motoneurone of 2 or more "motor subunits" in different muscles. Therefore we suggest that the motoneurone branches originate proximally from the primary trunk of the brachial plexus. Careful clinical and neurophysiological study can show these complex simultaneous innervations and also suggest correct kinesiotherapy.