Left lung — superior lobe

Function

The left upper lobe arches around the cardiac notch — the heart's rent in the lung's real estate — and carries the lingula, the tongue-like substitute for the missing middle lobe.

Three or four segments plus the lingula's two serve the left chest; the lobe's medial face is sculpted by the pericardium, and its apex, like the right's, tents above the first rib.

Blood supply

Left pulmonary artery's upper branches.

Nerve supply

Left pulmonary plexus.

Clinical relevance

Lingular pneumonia

Lingular consolidation blurs the left heart border on a frontal film (silhouette sign), while left lower lobe disease hides behind the heart.