Right phrenic nerve: anatomy, CT appearance, and differentiation from the pulmonary ligament.

The pulmonary ligament appears on computed tomographic (CT) sections as a thin, high-attenuation line, frequently seen above or at the level of the diaphragm and usually extending from the region of the esophagus. However, another line coursing laterally from the midportion of the inferior vena cava has also been identified as the pulmonary ligament. The authors examined sections from eight cadavers and 80 chest CT examinations to more clearly delineate the pulmonary ligament from this second structure. Anatomic and CT correlation proves that the line seen at the midportion of the inferior vena cava represents the right phrenic nerve and that the right pulmonary ligament is located posterior to it.