The human lungs have five lobes in total: three in the right lung and two in the left. The right lung contains the superior, middle, and inferior lobes, while the left lung has only a superior and inferior lobe.
Why the Left Lung Has Fewer Lobes
Your heart sits slightly left of center in your chest, and it needs room. The left lung has a small indentation on its inner surface called the cardiac notch, where the tip of the heart nestles against it. This takes up space that would otherwise hold lung tissue, which is why the left lung is both narrower and longer than the right. The right lung, with more room to work with, is shorter and broader and holds a greater volume of air.
Despite having one fewer lobe, the left lung still handles its share of breathing. Each lobe receives its own branch of the airway (called a secondary bronchus), so air flows independently into each one.
Smaller Divisions Inside Each Lobe
Each lobe is further divided into smaller, self-contained units called bronchopulmonary segments. Think of them as wedge-shaped sections, each with its own air supply and blood vessels. The right lung has 10 segments spread across its three lobes: three in the upper lobe, two in the middle lobe, and five in the lower lobe. The left lung has 8 to 10 segments depending on how you count, because some of the smaller segments tend to fuse together.
These segments matter most in a surgical context. When disease is limited to a small area, surgeons can sometimes remove individual segments rather than an entire lobe, preserving more healthy tissue.
What Happens When a Lobe Is Removed
A lobectomy, the surgical removal of one lobe, is one of the most common operations for lung cancer. It’s also used for conditions like tuberculosis, lung abscesses that don’t respond to antibiotics, emphysema, and benign tumors that press on blood vessels or nearby organs. The goal is to remove the diseased section before the problem spreads to other lobes.
After a lobe is removed, the remaining healthy lung tissue continues to function normally. Most people adapt well because the other lobes compensate for the lost capacity. Your total lung volume decreases, but for everyday activities, the remaining four lobes typically provide enough oxygen exchange to live without major limitations.
How the Five Lobes Work Together
Each lobe operates somewhat independently. Air enters through the windpipe, which splits into two main airways (one for each lung). Those airways then branch again, with each branch feeding a single lobe. This branching pattern means that a blockage or infection in one lobe doesn’t automatically compromise the others.
The right lung does more of the heavy lifting simply because it’s larger. Its three lobes give it roughly 55 to 60 percent of total lung capacity, while the left lung’s two lobes handle the rest. You don’t notice this imbalance during normal breathing because both lungs work in sync, expanding and contracting together with each breath.