Final answer:
The brachial plexus is a nerve plexus associated with the lower cervical spinal nerves and the first thoracic spinal nerve. It supplies nerves to the arm.
Step-by-step explanation:
The brachial plexus is a nerve plexus associated with the lower cervical spinal nerves and the first thoracic spinal nerve. It is responsible for supplying nerves to the arm. The brachial plexus is composed of spinal nerves C4 through T1, which reorganize to give rise to the nerves of the arms.
There are four main nerve plexuses in the human body, and each one is associated with different regions of the body. The cervical plexus supplies nerves to the posterior head and neck, the lumbar plexus supplies nerves to the anterior leg, and the sacral plexus supplies nerves to the posterior leg.