CT appearance of the normal inferior pulmonary ligament

The inferior pulmonary ligament, a double layer of pleura that tethers the lower lobe of the lung to the mediastinum, is rarely appreciated on plain radiographs but may be involved in pathologic processes. A linear structure on axial computed tomographic (CT) images of the lung bases corresponds to the inferior pulmonary ligament on cadaver sections. Review of 100 CT studies identified at least one inferior pulmonary ligament in 42%. Its presence and configuration did not correlate with patient age or gender. The anatomy and CT appearance of the ligament are discussed.