What innervates the lateral one third of the IVD?

What innervates the lateral one third of the IVD?

• A. Afferent branches from the sympathetic trunk
• B. Sinuvertebral nerve
• C. Gray ramus communicans
• D. Dorsal ramus

Answer: (C)

The nerves supplying the intervertebral disc include autonomic fibers that reach the disc through connections between the sympathetic system and the spinal nerves. In particular, postganglionic sympathetic fibers travel from the sympathetic trunk into the spinal nerves via the gray ramus communicans and then innervate structures around the spinal column, including the lateral portion of the annulus fibrosus. The sinuvertebral nerve does provide sensory input to the disc, especially to the posterior aspects, but the specific lateral one-third region is carried by the fibers in the gray ramus communicans. The dorsal ramus mainly serves the muscles and skin of the back, not the disc, and afferent branches directly from the sympathetic trunk don’t reach the disc as a distinct pathway.

The nerves supplying the intervertebral disc include autonomic fibers that reach the disc through connections between the sympathetic system and the spinal nerves. In particular, postganglionic sympathetic fibers travel from the sympathetic trunk into the spinal nerves via the gray ramus communicans and then innervate structures around the spinal column, including the lateral portion of the annulus fibrosus. The sinuvertebral nerve does provide sensory input to the disc, especially to the posterior aspects, but the specific lateral one-third region is carried by the fibers in the gray ramus communicans. The dorsal ramus mainly serves the muscles and skin of the back, not the disc, and afferent branches directly from the sympathetic trunk don’t reach the disc as a distinct pathway.