Which nerves supply the outer one-third of the intervertebral disc?

Which nerves supply the outer one-third of the intervertebral disc?

• A. Dorsal ramus
• B. Ventral ramus
• C. Recurrent meningeal nerve and grey ramus communicans
• D. Intercostal nerve

Answer: (C)

The outer one-third of the intervertebral disc is innervated by branches that re-enter the spinal canal to reach the disc itself. The main fibers come from the recurrent meningeal nerves (sinuvertebral nerves), which originate from the spinal nerve and re-enter through the intervertebral foramen to supply the posterior annulus fibrosus and the posterior longitudinal ligament. In addition, postganglionic sympathetic fibers travel in the grey rami communicans to the vessels in the outer annulus, contributing to sensation and blood supply in that region. The dorsal ramus mainly supplies paraspinal muscles and overlying skin, not the disc, and the intercostal nerves are not the primary source of disc innervation. Therefore, the combination of recurrent meningeal nerves and grey rami communicans best explains the innervation of the outer third.

The outer one-third of the intervertebral disc is innervated by branches that re-enter the spinal canal to reach the disc itself. The main fibers come from the recurrent meningeal nerves (sinuvertebral nerves), which originate from the spinal nerve and re-enter through the intervertebral foramen to supply the posterior annulus fibrosus and the posterior longitudinal ligament. In addition, postganglionic sympathetic fibers travel in the grey rami communicans to the vessels in the outer annulus, contributing to sensation and blood supply in that region. The dorsal ramus mainly supplies paraspinal muscles and overlying skin, not the disc, and the intercostal nerves are not the primary source of disc innervation. Therefore, the combination of recurrent meningeal nerves and grey rami communicans best explains the innervation of the outer third.