The spinal cord is the connection between the brain and just about everything below the chin. Most of the nerves that branch off of this important information highway are grouped together under the name of thoracic nerves.
The Thoracic Spinal Nerves
There are 24 pairs of nerves that exit the spinal column, split into three sections. The top of the column supplies the arm and the neck, and the bottom of the column innervates the legs. The middle 12 nerves are called the thoracic spinal nerves; these do a bit of everything.
First Thoracic Nerve
The first nerve branching from the thoracic spine enters the brachial plexus, a bundle of nerves that supplies the arms and upper back. This includes the skin and muscles of the limb. Organs are not controlled by these nerves; they are supplied directly by the brainstem.
Upper Thoracic Nerves
The next five thoracic nerves supply the intercostal muscles of the chest. Also, each nerve branches off towards the skin to supply the skin of the chest and upper back.
Lower Thoracic Nerves
Thoracic nerves 7 through 11 function in a similar manner to the upper thoracic nerves, except that these nerves supply the skin and intercostal muscles of the abdomen and lower back.
Twelfth Thoracic Nerve
The last thoracic nerve joins the iliohypogastric nerve (a branch from the first lumbar nerve) to supply the gluteus muscles and skin of the buttocks. Unlike the other thoracic nerves, this nerve does not pass between two ribs.