Figure 1.

Brachial plexus injuries in adults.

Injured nerves must regenerate over long distances to reinnervate targets such as denervated muscle and sensory targets in the hand. At a regeneration rate of 1mm/day in humans, as much as an 800 day delay may be incurred for axons to regenerate over a distance of a metre from the injury site to the denervated targets in the hand. Reinnervation of the hand almost never occurs even after surgical nerve repair in these situations.