The persistent left superior vena cava: anatomical study, pathogenesis and clinical considerations.

The persistence of a left superior vena cava (LSVC) is an intrinsically cardiac anomaly, which can lead to serious complications during catheterization via the subclavian or internal jugular vein. We found this anomaly during dissection associated with an abnormal origin of the vertebral artery originating from the aortic arch between the left common carotid and subclavian arteries. The LSVC coursed towards the right atrium through a very dilated coronary sinus ostium. No abnormality of the azygos system was found. A thorough anatomic description was then made with external and internal morphology. The embryonic development and variations are described. Radiological and clinical implications are discussed.