Lateral segmental bronchus of right lung
Bronchus segmentalis lateralis pulmonis dextri
- Latin synonym: Bronchus IV pulmonis dextri
- Synonym: Bronchus 4 of right lung; B4
- Related terms: Lateral segmental bronchus [B IV]
Definition
The lateral segmental bronchus of the right lung (B4), supplies the lateral segment (S4) of the right middle lobe. In the standard Boyden classification of bronchopulmonary segments, the right middle lobe bronchus divides into two segmental bronchi: the lateral segmental bronchus (B4) and the medial segmental bronchus (B5).
The right middle lobe bronchus arises from the bronchus intermedius (intermediate bronchus) after the takeoff of the right upper lobe bronchus. It typically bifurcates into B4 (lateral) and B5 (medial), a pattern seen in the vast majority of cases (~96%, 229/238 in one CT- based study), with a small minority showing trifurcation.
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