Nerve Supply for the Arms

Due to the extended range of motion of the arms, the nerves that enable their complex motor functions must cross the articulations that enable this range as close to the center of their rotational axis as possible.

Whereas in the Locomotive Core much of the movement patterns are organized on top of primitive reflexes (in essence commanding the activation of reflexes), in the Manipulation Core management of the arms is governed by the conscious control of our fine motor skills. The primitive reflexes are still present and are engaged when the arms are used in gait (crawling) but are suppressed for the complex motor functions which form the basis of tool use. This requires complex nerve paths that engage with the Neo-Cortical fine motor circuitry – from the hands to the modern brain, passing through but bypassing as much as possible the more primitive neurological layers.