Topics

Topic

design image
Lingular bronchus of left lung

The lingular bronchus is a major segmental branch of the left upper lobar bronchus, corresponding functionally to the middle lobe bronchus on the right. It arises after the division of the upper lobar bronchus and descends anteroinferiorly to supply the lingula of the left lung. The lingular bronchus typically divides into two segmental branches: the superior lingular bronchus (B4) and the inferior lingular bronchus (B5). Together, they ventilate the lingular division of the left upper lobe, which lies adjacent to the heart, explaining its name (“lingula” = “little tongue”).

Synonyms

  • Bronchus lingularis

  • Lingular division bronchus

  • Lingular segmental bronchus of left upper lobe

Function

  • Conducts air to the lingula of the left upper lobe, including both B4 and B5 segments

  • Supports gas exchange in the lingular division

  • Plays a role in mucus clearance from the lingula

  • Important surgical landmark in lingular segmentectomy or lobectomy planning

CT Appearance

Lung Window:

  • Seen as an air-filled, hypodense (black) bronchial lumen branching anteroinferiorly from the left upper lobar bronchus

  • Normally thin-walled and patent

  • Pathology: wall thickening (bronchitis), mucus plugging, or endobronchial lesions may cause partial or complete obstruction

Mediastinal Window:

  • Bronchial wall is visible as a thin soft tissue rim

  • Useful for assessing the relationship of the lingular bronchus to adjacent pulmonary vessels, pericardium, and lymph nodes

  • Helps detect extrinsic compression or peribronchial infiltration

Contrast-enhanced CT (CECT):

  • Shows enhanced definition of the bronchial wall and adjacent vasculature

  • Detects bronchial stenosis, endobronchial tumors, or peribronchial lymphadenopathy

  • High-resolution CT (HRCT) provides fine detail of bronchial lumen caliber, branching, and segmental anatomy

MRI Appearance

T1-weighted images:

  • Air-filled bronchial lumen appears as a signal void (black)

  • Bronchial wall shows low signal intensity, with peribronchial fat appearing hyperintense

T2-weighted images:

  • Air-filled lumen remains a signal void

  • Mucus or fluid in the bronchus appears bright hyperintense

  • Inflamed or thickened bronchial walls show intermediate to hyperintense signal

T1 Post-Contrast (Gadolinium-enhanced):

  • Normal bronchial wall enhances as a thin rim

  • Pathological changes (tumor, granulomatous disease, bronchitis) demonstrate thickened, irregular, heterogeneous enhancement

CT image

Lingular bronchus of left lung anatomy CT coronal image -img-00000-00000