Why can people with NEO's kind of neck injury lift the arm but not grasp? · Grey Matter

Each segment of the cord sends motor nerves to its own muscles, and an injury cuts the commands to every segment below it.

Why can people with NEO's kind of neck injury lift the arm but not grasp?

Each segment of the cord sends motor nerves to its own muscles, and an injury cuts the commands to every segment below it. The shoulder and elbow are served mostly from C5 and C6, while the muscles that bend and spread the fingers are wired from C7 to T1, the lowest segments of the neck and the first of the chest. An incomplete injury in the neck can therefore leave a person able to raise the arm and bend the elbow with no working grip, which is the gap NEO fills by reading the intention to grasp from the cortex and handing it to a powered glove.