The benefits of ultrasound guidance for IJ CVC placement are well established. However, the benefits of ultrasound guidance may be extended by more fully evaluating both the left and right IJ prior to choosing a side for placement. As mentioned previously, several factors could make placement of the CVC on a particular side either more successful or precarious. These factors include possible asymmetric diameter of the IJ vein, unfavorable relationship of the IJ to the carotid artery, pre-existing IJ thrombus, or other aberrant vascular anatomy.