Location of the Lingular Lobe
The lingular lobe (or lingula) is located in the left upper lobe of the lung, specifically comprising the anterior-inferior portion of the left upper lobe.
Anatomical Position and Structure
The lingula is not a separate lobe but rather a subdivision of the left upper lobe that corresponds anatomically to the right middle lobe 1. It consists of two distinct segments:
- Superior lingular segment (B4) - the upper portion
- Inferior lingular segment (B5) - the lower portion 2, 3
Anatomical Boundaries
The lingula is separated from the anterior segment of the left upper lobe by an important vascular landmark 1:
- Superior boundary: The lower branch of the draining vein of the anterior segment (V3b) runs horizontally and serves as the anatomical dividing line between the anterior segment and the lingular division 1
- Inferior boundary: Extends down toward the oblique fissure, adjacent to the left lower lobe
Bronchial Anatomy
The lingular division bronchus branches from the left upper lobe bronchus and typically bifurcates into 2:
- Superior lingular segmental bronchus (B4)
- Inferior lingular segmental bronchus (B5)
Important anatomical variation: In rare cases (0.6% of patients), the lingular bronchus may bifurcate horizontally into lateral (B4) and medial (B5) segments rather than the typical superior-inferior pattern 2. Additionally, displaced anomalous lingular bronchi have been reported, where the lingular bronchus may branch from the left lower lobe bronchus stem rather than the typical location 4.
Vascular Supply
The lingular segments receive arterial supply through variable patterns 3:
- Single artery: 45.18% of cases
- Two arteries: 46.39% of cases
- Three arteries: 8.43% of cases
The arterial origin includes interlobar lingular arteries (71.68%), combined interlobar and mediastinal origin (21.08%), or purely mediastinal origin (7.83%) 3.
Clinical Relevance
Understanding lingular anatomy is essential for thoracic surgeons performing anatomical resections, as the bronchovascular patterns show significant variation 5, 3. The lingula can be identified on CT imaging, and thin-section CT is particularly helpful for precisely identifying the lingular bronchial tree and localizing lesions 1.