The nerves are grouped into five primary regions based on the segment of the spinal cord they extend from:

12 pairs in the upper and middle back that supply the chest and abdominal muscles.

The spinal cord ends around L1–L2 in adults; below that, the cauda equina (nerve roots) continues.

Vertebrae Nerve Map -

The nerves are grouped into five primary regions based on the segment of the spinal cord they extend from:

12 pairs in the upper and middle back that supply the chest and abdominal muscles.

The spinal cord ends around L1–L2 in adults; below that, the cauda equina (nerve roots) continues.