The anterior junction line (AJL), the sterno-aortic distance and the sagittal thoracic diameter were measured in CT sections at the carinal level in 22 patients with emphysema and 22 controls. The measured distances were all significantly larger in the emphysema patients. An AJL of 3 cm or more and a sterno-aortic distance of 4 cm or more was found in respectively 10 and 16 of the 22 emphysema patients but in none of the control patients.