Objective: To determine the success rate and complications of using the external jugular vein (EJV) for central venous access with a preoperative estimate of the detailed anatomical orientation of the cervical venous plexus using computed tomography venography (CT-V). Design: Prospective, observational human study. Setting: Surgical intensive care unit. Patients: Fifty-two patients who were undergoing EJV cannulations with CT-V using a Multidetector Helical 16-section CT (MDCT). Intervention: The preoperative anatomical estimation of the cervical venous plexus was performed with CT-V using an MDCT. In particular, the angulation between the EJV and the right subclavian vein (SCV) was measured. The anatomical abnormalities and the angulation between the EJV and the anterior jugular vein (AJV), transverse cervical vein (TCV), and suprascapular vein (SSV) were estimated. Measurements and Main Results: The success of CT-V was achieved in 52 of 52 patients (100%). The mean angulation between the right EJV and the right SCV was 144 +/- 36 degrees in the obtuse-angle cases (88%) and 72 +/- 28 degrees in the sharp-angle cases (12%). A plexus of veins under the clavicle was most commonly responsible for insertion of the central venous catheter (CVC). The EJV approach resulted in a 93% rate of successful cannulations. No complications of pneumothorax or carotid artery puncture occurred during insertion procedures. Conclusions: The EJV route is associated with comparable technical success and lower major procedural complication. The EJV approach with CT-V guidance is an option as the initial method when central venous cannulation must be performed under suboptimal conditions.