lung lobe

A lung lobe is one of the big, naturally separated chunks that make up each lung — rather like the large segments you can pull apart in an orange. Each lobe receives its own large bronchus and its own blood supply, and is wrapped by infoldings of the lung’s surface membrane.

The right lung has three lobes (upper, middle and lower), while the left has only two (upper and lower), making room on the left for the heart. The grooves between lobes are called fissures. The left upper lobe carries a small tongue-shaped projection, the lingula, that roughly mirrors the right middle lobe.

Lobes are practical units in medicine. Pneumonia may settle in a single lobe (lobar pneumonia), surgeons may remove a whole diseased lobe (lobectomy), and describing which lobe is involved helps localise findings on a chest X-ray or CT.