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Right inferior lobar bronchus

The right inferior lobar bronchus, also called the right lower lobe bronchus, is a major division of the right main bronchus that supplies the right lower lobe of the lung. It arises at the level of the hilum after the origin of the right superior and middle lobar bronchi, and courses downward and posteriorly toward the inferior lobe.

It divides into five segmental bronchi (segmental bronchi are the functional airways supplying bronchopulmonary segments of the right lower lobe): the superior (S6), medial basal (S7), anterior basal (S8), lateral basal (S9), and posterior basal (S10) bronchi. These airways correspond to distinct bronchopulmonary segments, each with its own vascular and bronchial supply.

Anatomically, the right inferior lobar bronchus is shorter and steeper than its left counterpart due to the orientation of the right lung and hilum. It is of major clinical importance in bronchoscopy, pulmonary surgery, segmentectomy, lobectomy, and imaging evaluation of lung disease.

Synonyms

  • Right lower lobe bronchus

  • Bronchus lobaris inferior dexter

  • Right basal bronchus

Function

  • Provides airflow to the right lower lobe of the lung

  • Supplies oxygen to the superior and basal bronchopulmonary segments (S6–S10)

  • Acts as a key anatomical landmark during bronchoscopy and lung surgery

  • Contributes to airway clearance through ciliary action and mucus transport

Branches (Segmental Bronchi)

  • Superior segmental bronchus (S6)

  • Medial basal bronchus (S7)

  • Anterior basal bronchus (S8)

  • Lateral basal bronchus (S9)

  • Posterior basal bronchus (S10)

MRI Appearance

T1-weighted images:

  • Appears as a low-signal branching tubular structure, with adjacent peribronchial fat hyperintense aiding localization

  • Air within the lumen produces a signal void

T2-weighted images (normal):

  • Lumen appears as a signal void due to air

  • Surrounding bronchial wall is seen as a thin hypointense rim; peribronchial pathology (e.g., edema or inflammation) appears hyperintense

T2 TRUFISP (cardiac/respiratory-gated):

  • Clearly shows the bronchial tree as dark branching lumens against bright lung parenchyma

  • Excellent for visualizing segmental divisions and dynamic motion with respiration

STIR (Short Tau Inversion Recovery):

  • Fat suppression improves contrast between bronchus and mediastinal fat

  • Highlights peribronchial edema, inflammation, or tumor spread as hyperintense changes

T1 Post-Contrast (Gadolinium-enhanced MRI):

  • Bronchial walls may enhance mildly

  • Abnormal enhancement may indicate bronchial inflammation, tumor, or vascular encasement

MRI Non-Contrast 3D Cardiac/Respiratory-Gated Imaging:

  • Provides 3D reconstruction of bronchial tree, including the right inferior lobar bronchus and its five segmental branches

  • Useful in mapping bronchial anatomy prior to surgery or interventional procedures

  • Particularly valuable in patients where contrast is contraindicated

CT Appearance

High-Resolution CT (HRCT):

  • Right inferior lobar bronchus visualized as a tubular air-filled structure arising from the right main bronchus and coursing inferiorly

  • Segmental bronchi (S6–S10) well seen in coronal and sagittal reformats

  • Detects bronchiectasis, stenosis, obstruction, or external compression

CT Coronary Angiography (CCTA) / Pulmonary CT Angiography:

  • Clearly demonstrates the bronchovascular relationships of the right inferior lobar bronchus with adjacent pulmonary arteries and veins

  • Useful for differentiating bronchial vs vascular structures in hilar and segmental anatomy

  • Multiplanar and 3D reconstructions aid preoperative planning in lobectomy or segmentectomy

CT image

Right inferior lobar bronchus anatomy CT coronal image -img-00000-00000

MRI image

Right inferior lobar bronchus anatomy MRI coronal image -img-00000-00000