Distribution of Spinal Nerves

The cervical plexus is the plexus of the ventral rami of the first four cervical spinal nerves.

The brachial plexus is formed by the four lower cervical spinal nerves and the first thoracic spinal nerve.

The lumbar plexus is formed by the subcostal nerve and divisions of the first four lumbar nerves that arise from the middle to lower back.

The sacral plexus is the plexus of the three sacral spinal nerves (S2–S4) that arise from the lower back just above the sacrum.

The spinothalamic tract is a somatosensory tract and the corticospinal tract is a motor tract.