Lingular bronchus of left lung

The left upper lobe bronchus is very short. It rapidly divides into two main branches : the upper division of left superior lobar bronchus (upper lobe bronchus proper) which further branches into the apicoposterior segmental bronchus (B1+2) and the anterior segmental bronchus (B3). and the lingular bronchus that divides into two segmental bronchi : the superior lingular segmental bronchus of left lung (B4) and the superior lingular segmental bronchus of left lung (B5).

The terms upper lobe bronchus proper and lingular bronchus are not officially listed in the Terminologia Anatomica, because they cant be considered as a lobar or a segmental bronchus. But as they correspond to the superior lobar bronchus and the middle lobar bronchus of the right lung, these terms are widely used in daily practice for radiologists, pneumologists and thoracic surgeons.