Der Schmerz
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Present-day hypotheses about the origin of pain in deep tissues are based on the idea that pain is anindependent sensation with its own specialized apparatus of sensors, conduction pathways and centers. The sensors are callednociceptors ornocisensors, and the neuronal structures they activate are thenociceptive system. Accordingly, the reception, conduction and central nervous processing of noxious signals together are termednociception. ⋯ Finally an account is presented of pain produced by excitation of the nociceptive system proximal to the nociceptors. These pain states include pain resulting from pathophysiological impulse generation in nociceptive fibers (neuralgia orneuralgic pain) which usually projects into the region containing the sensory endings of these fibers (projected pain). Furthermore, brief descriptions of pain due to spinal root compression and ofcentral pain arising from various sites of the central nervous system are given.