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Inferior lobe of right lung

The inferior lobe of the right lung (right lower lobe) is the largest and most posterior lobe of the right lung. It occupies the lower portion of the right hemithorax and plays a major role in gas exchange due to its large volume and dependent position.

It is an important anatomical region in thoracic anatomy and imaging, serving as a key landmark in chest radiography and cross-sectional imaging.

Synonyms

  • Right lower lobe

  • Inferior lobe of right lung

Location

  • Located in the lower part of the right hemithorax

  • Inferior to the oblique fissure

  • Posterior and inferior to the right upper and middle lobes

  • Extends from the hilum posteriorly to the costophrenic recess

  • Rests on the right hemidiaphragm

  • Forms the majority of the posterior lung field

Anatomical components

  • Bronchial supply:

    • Right lower lobe bronchus (branch of the right main bronchus)

  • Segments:

    • Superior segment (S6)

    • Medial basal segment (S7)

    • Anterior basal segment (S8)

    • Lateral basal segment (S9)

    • Posterior basal segment (S10)

  • Vascular structures:

    • Segmental pulmonary arteries and veins

  • Parenchyma:

    • Alveoli and interlobular septa

Relations

Superiorly:

  • Oblique fissure

  • Right upper and middle lobes

Inferiorly:

  • Right hemidiaphragm

  • Liver (through diaphragm)

Anteriorly:

  • Middle lobe (limited contact)

Posteriorly:

  • Posterior thoracic wall

  • Paravertebral region

Medially:

  • Right hilum

  • Mediastinum

X-ray appearance

Chest radiograph (PA and lateral views):

  • PA view:

    • Forms the lower zone of the right lung field

    • Bordered inferiorly by the right hemidiaphragm

  • Lateral view:

    • Occupies the posterior and inferior portion of the lung

    • Lies behind the heart and major fissure

  • Costophrenic angle:

    • Inferior lobe extends into the posterior costophrenic recess

CT appearance

CT lung window:

  • Parenchyma: Normal aerated lung with low attenuation

  • Bronchi: Visible segmental and subsegmental bronchi with thin walls

  • Vessels: Pulmonary arteries and veins branching toward the periphery

  • Interlobular septa: Thin and usually not conspicuous

  • Fissure relationship: Clearly separated from upper and middle lobes by the oblique fissure

MRI appearance

T1-weighted images:

  • Lung parenchyma: Low signal intensity due to air content

  • Vessels and bronchi: Intermediate signal structures within low-signal lung

  • Diaphragm interface: Well delineated inferior border

T2-weighted images:

  • Lung parenchyma: Low signal intensity

  • Pulmonary vessels: Intermediate-to-high signal relative to lung

  • Pleural surfaces: Thin low-signal lines

STIR:

  • Lung parenchyma: Predominantly low signal

  • Soft tissues and pleura: Higher signal compared with aerated lung

CT image

Inferior lobe of right lung of right lung CT anatomy image -img-00000-00000

CT image

Right Lung Inferior Lobe_ Anatomy, Location and Imaging Appearance CT anatomy image -img-00000-00000

X-Ray image

Inferior lobe of right lung X RAY anatomy image -img-00000-00000