Innervation of the lumbar spine.

Back pain, in spinal stenosis, can arise from many sources. Apart from nerve root involvement any of the structures considered above can be implicated. In degenerative conditions, where discogenic and posterior facet pain are present, excess activity tends to increase these symptoms. In addition there is evidence that impulses reaching the spinal nerve root through the sinu-vertebral nerve and possibly the posterior ramus may potentiate the irritability of that root. Whether such a mechanism contributes to the claudication of degenerative spinal stenosis is not known.