Categories of abdominal pain
1. Visceral pain occurs when noxious stimuli affect an abdominal viscus. The pain is usually dull (cramping, gnawing, or burning) and poorly localized to the ventral midline because the innervation to most viscera is multisegmental. Secondary autonomic effects such as diaphoresis, restlessness, nausea, vomiting, and pallor are common.
2. Parietal pain occurs when noxious stimuli irritate the parietal peritoneum. The pain is more intense and more precisely localized to the site of the lesion. Parietal pain is likely to be aggravated by coughing or movement.
3. Referred pain is experienced in areas remote from the site of injury. The remote site of pain referral is supplied by the same neurosegment as the involved organ; for example, gallbladder pain may be referred to the right scapula and pancreatic pain may radiate to the midback.
