An unusual case of the cephalic vein with a supraclavicular course.

While the subclavian or axillary vein can be safely and successfully punctured in the majority of cases, some device implanters still prefer cut down to the cephalic vein as the initial approach to venous access for transvenous placement of pacemaker or defibrillator leads out of concern for the risk of pneumothorax, subclavian crush, and other possible complications. However, very occasionally, the cephalic vein crosses superficial to the clavicle to join the external jugular vein, making it rather unappealing for this purpose. Relying on a guide wire introduced through the cephalic vein to guide puncture of the subclavian vein is unlikely to be successful in such a situation and may cause accidental damage to the vital structures in the thoracic inlet region. Device implanters need to be aware of this anatomical anomaly because of the implications for transvenous lead placement.