Right lung, middle lobe

Lobus medius pulmonis dextri

RespiratoryOrgansThoraxRight side

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What it is
A wedge-shaped lobe at the front and lower part of the right lung, between the horizontal fissure (4th costal cartilage) and the oblique fissure.
Function
Gas exchange; ventilated by the middle lobe bronchus through its lateral and medial segments.
Size
The smallest lobe, roughly 10% of total lung volume.
Clinical note
Its long, narrow bronchus makes it prone to collapse (middle lobe syndrome); consolidation here blurs the right heart border on a chest X-ray (silhouette sign).

Part of Visceral pleura

Nearby respiratory structures Right anterior basal segmental bronchus (B8), Right lateral basal segmental bronchus (B9), Right lateral segmental bronchus (B4), Right lower lobe bronchus, Right lung, lower lobe, Right medial basal segmental bronchus (B7), Right medial segmental bronchus (B5), Right middle lobe bronchus, Right posterior basal segmental bronchus (B10), Right superior segmental bronchus (B6)