The term "plexic hand" refers to hand and wrist involvement in traumatic brachial plexus injuries and to remaining deficits after nerve surgery has been performed. From January 2000 to March 2008, reconstructive surgery (dynamic tenodesis) was performed on seven patients with C5, 6, 7, and 8 nerve root lesions of the brachial plexus to restore wrist and finger extension. This procedure has been used in seven patients (one female). Two patients with a lesion of the brachial plexus sustained a fracture of the affected limb. Preliminary nerve repair operations were required in four cases. One hundred percent (seven) of the patients had improved function following dynamic tenodesis. The extension angle of the wrist joint on grip was 19° on average. The flexion angle of the wrist joint needed to produce MP joint extension was 24.3° on average. A new dynamic extensor tenodesis technique is proposed. The extensor digitorum communis tendons are looped through dorsal carpal retinaculum ligament and sutured to themselves. Our results demonstrate that the extensor dynamic tenodesis procedure is an effective and simple means of restoring grip function for patients with C5, 6, 7, and 8 nerve root lesions.