Which of the following is true about intercostal nerves?

Intercostal nerves primarily serve the function of supplying the intercostal muscles, which are essential for the mechanics of breathing. These nerves emerge from the thoracic spinal cord and run along the spaces between the ribs, directly innervating the intercostal muscles. When these muscles contract, they help to expand and contract the rib cage during respiration, thus playing a crucial role in breathing.

Understanding the functionality of intercostal nerves also highlights their importance in the overall respiratory process, as they aid not only in the movement of ribs but also assist in ensuring effective lung ventilation. This relevance to respiration underscores why the correct choice focuses on their role in innervating the intercostal muscles specifically, which correlate directly to respiratory mechanics.