The most important characteristic of visceral pain is its indefinite location. Patients with abdominal pain are usually unable to name the exact location of the pain themselves, which is related to the distribution of visceral nociceptive receptors. This is related to the distribution of visceral nociceptive receptors. The distribution is sparser than that of the trunk, and the afferent pathways of visceral sensation are more dispersed. Pain occurs slowly and lasts longer, which means that it is slow and progressively increasing, but sometimes it can rapidly turn into severe pain with a higher pain threshold. The main reason for this is that the number of visceral sensory fibers is relatively small and slender, and the pain threshold is very high, so that patients do not feel the normal intensity of stimulation.