The
brachial plexus is a network of
nerves, running from the
spine, formed by the
anterior rami of the lower four cervical nerves and first thoracic nerve (
C5–
C8,
T1). The brachial plexus passes through the
cervicoaxillary canal in the neck, over the first rib, and into the
axilla (armpit region), where it innervates the upper limbs and some neck and shoulder muscles.