The eighth thoracic dorsal spinal rami run posteriorly, adjacent to the zygapophyseal joints between T8 and T9 and divide into medial and lateral branches.

The lateral branches emerge between the superior costotransverse ligaments and the intertransversarii muscles and pass between the longissimus thoracis and iliocostalis cervicis muscles to reach the medial border of levatores costarum.  At the costal angles they give off cutaneous branches, which pierce latissimus dorsi and descend several vertebral levels to terminate in the overlying skin.

Supply
The lateral branches of the eighth thoracic dorsal spinal rami supply the multifidus, longissimus thoracis, iliocostalis cervicis, levatores costarum and interspinales muscles; they also supply skin overlying latissimus dorsi.