Benign anatomical mistakes: inferior pulmonary ligament.

The term inferior pulmonary ligament needs to be revised. There is no superior component to oppose the inferior. By all means the pulmonary ligament is not a ligament, and the term ligament should be reserved for regularly oriented thick connective tissue bundles between bones. The term triangular ligament describes its shape but not its topography. For most surgeons the broad ligament refers, rather, to the ligament of the uterus. Embryologically pulmonary ligament is a "meson" i.e., a remnant of the developmental pathway--the pleural fold in this case--and taking this into consideration the most convenient term seems to be mesopneumonium. Its upper part is related to the hilar area, and its lower free border is what we call pulmonary ligament. We suggest the term mesopneumonium to describe the whole "meson" from the mediastinum to the hilum, which corresponds better to topography, embryology, and function.