Coloured frontal X-ray of the thorax of a 68-year-old male patient with pain in the chest. The X-ray shows deformation of the right cardiovascular contour, suggestive of a ascending thoracic aortic aneurysm (centre). Aneurysms are localised, blood-filled balloon-like bulges in the wall of a blood vessel. They form when the wall is weakened by disease or another cause.