Right lung — middle lobe

Function

The middle lobe is a small triangular wedge slotted between the horizontal and oblique fissures on the anterior chest. Its bronchus is long, narrow and surrounded by lymph nodes — a triple vulnerability to blockage.

Its two segments (medial and lateral) lie against the right heart border — collapse or pneumonia here blurs that border on a frontal chest film (silhouette sign).

Blood supply

Right pulmonary artery branches.

Nerve supply

Right pulmonary plexus.

Clinical relevance

Middle lobe syndrome

Chronic collapse from lymph node compression or mucus plugging — recurrent infection needing bronchoscopic clearance.

Right middle lobe pneumonia

Classic lobar pneumonia fills this lobe, silencing breath sounds at the right anterior mid-chest.