Lingula of left lung

According to most sources, there is no middle lobe in the left lung as there is in the right lung. However, the term lingula is used to denote a projection of the upper lobe of the left lung that serves as the homologue, and some sources define this as a distinct lobe.

There are two bronchopulmonary segments of the lingula: Superior and inferior.

It is thought that the lingula of the left lobe is the remnant of the right lobe of the lung, which has been lost from the left through evolution