"True" intercostal hernias, that is, those containing both pleura and lung components, occur infrequently. Only 300 cases have been reported since Rolland’s initial description in 1499. Rarer still are intercostal muscle hernias, which occur without containing pulmonary components. In both instances, males predominate, usually a consequence of direct blunt chest trauma. In many instances, recognition of the intercostal muscle hernia may be delayed from weeks to months, its diagnosis masked by more obvious evidence of physical trauma.