This study investigated the anatomical relationship between the clavicle and its adjacent vascular structures, in order to define safe zones, in terms of distance and direction, for drilling of the clavicle during osteosynthesis using a plate and screws following a fracture. We used reconstructed three-dimensional CT arteriograms of the head, neck and shoulder region. The results have enabled us to divide the clavicle into three zones based on the proximity and relationship of the vascular structures adjacent to it. The results show that at the medial end of the clavicle the subclavian vessels are situated behind it, with the vein intimately related to it. In some scans the vein was opposed to the posterior cortex of the clavicle. At the middle one-third of the clavicle the artery and vein are a mean of 17.02 mm (5.4 to 26.8) and 12.45 mm (5 to 26.1) from the clavicle, respectively, and at a mean angle of 50° (12 to 80) and 70° (38 to 100), respectively, to the horizontal. At the lateral end of the clavicle the artery and vein are at mean distances of 63.4 mm (46.8 to 96.5) and 75.67 mm (50 to 109), respectively. An appreciation of the information gathered from this study will help minimise the risk of inadvertent iatrogenic vascular injury during plating of the clavicle.