Question: Where do all nerves in the arm root from?
Disambiguated questions and answers: question: Where from the spinal cord does the nerves in the arm root from?
Where do the nerves in the arm root from in a network?
answer: anterior rami of the lower four cervical nerves and first thoracic nerve
brachial plexus
Natural Questions answer: brachial plexus (from the Wikipedia article "Brachial plexus")