Acute cholecystitis produces discomfort in the right upper quadrant or epigastrium. Inflammation of the gallbladder may cause irritation of the subdiaphragmatic parietal peritoneum, which is supplied in part by the phrenic nerve (C3, 4, and 5). This may give rise to referred pain over the shoulder, because the skin in this area is supplied by the supraclavicular nerves (C3 and 4).
Definition