Exclamation mark sign (limy bile)

The exclamation mark sign is a pathognomonic imaging sign of the rare diagnosis of limy bile on plain abdominal radiography. It occurs when there is both limy bile and a gallstone in the common bile duct. The linear vertical radiopaque bile forms the line of the exclamation mark (i.e. !), whilst a more distal calculus forms the 'dot' at the end of the exclamation mark ¹.