Final answer:
External intercostal motor nerves are systemic nerves arising from thoracic spinal nerves T2 through T11. They are located in the intercostal spaces, laterally on the sides of the body, and innervate the external intercostal muscles which are essential for inspiration during breathing.
Step-by-step explanation:
Location of External Intercostal Motor Nerves
The external intercostal muscles are vital for the process of breathing, particularly during inspiration. These muscles are located laterally on the sides of the body, spanning between the ribs. The intercostal nerves, which specifically control these muscles, originate from the spinal nerves in the thoracic region, from T2 through T11. These nerves are not part of a larger nerve plexus but are instead individually responsible for innerving the intercostal spaces where they reside.
The intercostal nerves are essentially systemic nerves located in the thoracic cavity and found between two ribs. The contraction of the external intercostal muscles, facilitated by these nerves, elevates the rib cage which in turn expands it, thus aiding in the intake of air during inspiration. Compared to the external intercostals, the internal intercostal muscles and the innermost intercostal muscles are used for expiration and act as synergists, respectively.