Bronchial Tree

Sometimes the atrophy of the mucosa is so marked that it allows to explore bronchi of 4th and 5th order.

Another variant very common in the lower left lobe, its division into two small trunks containing the three basal.

Accustomed distribution “in line” of the three left basal: anterior (LB8) here at 12 o’clock and partially hidden by the bronchial wall, medial (LB9) in the center and posterior segmental (LB10) below.

Close view at hour 3 of the entrance to the apical segment of the left upper lobe (LB6).
In its natural position, it is the first one that appears when leaving the upper left lobe bronchus.

A view of the lingular bronchus and its divisions in superior (LB4) at hour 11 and to its right the inferior (LB5).

From left to right: segmental medial (RB5) and lateral (RB4) of the middle lobe bronchus.

Division between the anterior segment (LB3) at hour 3 and the apicoposterior (LB1+2) at hours 8 and 10) of the left upper lobe.

Entrance to the left upper lobe.

In the background on the right, the bronchus of the lingula and on its left, at 10 o’clock, the small bronchial passage culminate, until its division, which is not observed here, in anterior segmental (LB3) and apicoposterior (LB1+2).

Image of the secondary carina that separates the upper and lower left lobular.
The area is also called a crossroads or “carrefour”.

View of the left main bronchus, with its separation angle from the midline of about 70° and its normal length from 20 to 55 millimeters.

Cytological brush about to enter a segmental bronchus to obtain a cellular sample by abrasion, for study.