Anatomy of the Visceral Nerves

To give a clear and concise description of visceral pain, it is necessary to start by introducing the anatomy of the visceral nerves which are complicated and closely related to the activation of sensations. The visceral nerves are divided into visceral motor nerves and visceral sensory nerves. A comparison of visceral motor nerves and somatic motor nerves will be made to reveal the unique features of visceral motor nerves. Then, sympathetic nerve, parasympathetic nerve, visceral plexuses, and enteric nervous system will be introduced, as they all play an indispensable and crucial role in consisting of the visceral motor nerves. The visceral sensory nerves section covers the concepts of interoceptor and neural pathways. Besides, referred pain is also illustrated as it is an important physiological characteristic of visceral sensation. It is a sensory hypersensitivity or nociception phenomenon in a certain area of the body surface. The detailed classification and explanation of visceral nerves will lay a solid foundation for further discussion of visceral pain and diseases.