Spasm of smooth muscles of internal organs (peptic ulcer, cholecystitis); stretching of the walls of hollow organs (gallbladder, renal pelvis, ureter); the spread of the inflammatory process to areas equipped with sensitive innervation (to the parietal pleura, peritoneum, etc.). The defeat of the brain substance is not accompanied by B., it occurs when the membranes, venous sinuses, and intracranial vessels are irritated. Pathological processes in the lung are accompanied by B. only when they spread to the parietal pleura. Strong B. arise with spasm of the vessels of the heart.
In the esophagus, stomach and intestines often occurs when they are spastic or stretched. Pathological processes in the parenchyma of the liver, spleen, and kidneys do not cause pain if they are not accompanied by acute stretching of the capsule of these organs. Muscle pain occurs with bruises, myositis, convulsions, arterial circulation disorders (in the latter cases, B. proceeds as sympathetic). With the defeat of the periosteum and bone processes B. have an extremely painful character.