Anesthesiologists and algologists must undersTand the somatic and visceral pathways of the body in order to perform efficient and accurate local anesthetic injections. There is considerable variation in the pathways of both visceral and somatic nerves. Nonetheless, it is useful for the practitioner to have some idea of these pathways. The sensory innervation of the skin is called dermatomes (Fig. 1.1). The sensory innervation of the bones is called sclerotomes