Tonkin I L, Keats T E, Capp M P
AJR Am J Roentgenol. 1977 Oct;129(4):657-9. doi: 10.2214/ajr.129.4.657.
On the lateral chest radiograph, the posterior wall of the inferior vena cava is an almost constant structure in the posterior cardiophrenic angle. Recently the anterior as well as the posterior walls of the vein have been noted in several patients. The "isolation" of the inferior vena cava, creating a linear density on the lateral chest radiograph, is a normal variant and should not be mistaken for chest pathology.