Microdissection and histologic studies were undertaken to determine the innervation of the cervical intervertebral discs. The cervical sinuvertebral nerves were found to have an upward course in the vertebral canal, supplying the disc at their level of entry and the disc above. Branches of the vertebral nerve supplied the lateral aspects of the cervical discs. Histologic studies of discs obtained at operation showed the presence of nerve fibers as deeply as the outer third of the anulus fibrosus. These anatomic findings provide the hitherto missing substrate for primary disc pain and the pain of provocation discography.