Innervation of the anterior spinal canal: an update.

Understanding the innervation of the lumbar spine can be a daunting task. Until recently, only macroscopic visualization and crude histological techniques were available to document the presence of nerve fibers in the anterior spinal canal. Using newer immunohistochemical techniques, studies have been able to more thoroughly investigate the innervation of the anterior spinal canal. The presence of sensory nerve fibers has been definitively identified in all anterior spinal structures. These sensory fibers enable any of the spinal structures the capability of being a pain generator. These sensory nerve fibers tend to form dense interwoven plexuses on the posterior longitudinal ligament and ventral surface of the dura mater. The plexuses allow for anastamoses to take place between nerve fibers from multiple segmental levels. This polysegmental formation causes the expression of low back pain to be diffuse, rather than focal. It is these diffuse pain symptoms that create great difficulty in diagnosing and treating spinal canal structures.