In addition to these major branches, small collateral branches can be found in the intercostal space running along the superior border of the lower rib.
In the thorax, the intercostal nerves carry: somatic motor innervation to the muscles of the thoracic wall (intercostal, subcostal, and transversus thoracis muscles), somatic sensory innervation from the skin and parietal pleura, and postganglionic sympathetic fibers to the periphery.