The calcium sign is a finding on chest x-ray that suggests aortic dissection. It is the separation of the intimal calcification from the outer aortic soft tissue border by 10mm. <a class="external" href="http://en.wikipedia.org/wiki/Aortic_dissection" rel="nofollow" target="_blank">(http://en.wikipedia.org/wiki/Aortic_dissection)</a> This is not an important sign for radiographers given that it is rarely seen.
Plain film Appearance
The arrowed distance represents a normal aortic wall thickness The arrowed distance represents the aneurysmal wall thickness.