This study was a retrospective investigation of computed tomography (CT) images of an Australian adult hospital population. These images were used to evaluate the spatial relationships of the superior vena cava (SVC) to the midsagittal line, the sternal paracoronal plane, and commonly used landmarks of the sternum. Consistent relationships were found between the long axis of the SVC and both the midsagittal line and sternal paracoronal plane. When the sternal paracoronal plane was used as the plane of reference, the angle of Louis was found to approximate the SVC in 99.5% of cases, and the right 2nd intercostal space approximated the SVC in 94% of cases. Constraints on the use of landmarks are discussed with regard to magnetic guidance systems for catheter tracking.