Painful lumbosacral sensory distribution patterns: embryogenesis to adulthood.

When the dorsal root ganglion is irritated by any of a variety of mechanisms, pain is referred to the various structures innervated by that root. In many circumstances, this pain is specific and may be used as a diagnostic aid. Unfortunately, emphasis is placed on defining a dermatomal distribution; the existence of a myotomal or sclerotomal origin of referred pain is often overlooked. This review presents the embryologic, anatomic, and neurophysiologic etiology of referred pain from the lumbar spine.