Thoracic Surgeries Simplified

So lung anatomy, a refresher, the basics, very simple, the things that you need to know in practice.

First, there are two lungs, obviously the right and the left, and sitting in the middle is the heart.

How simple is that? The right lung, the right lung has three lobes, which is the upper, middle, and lower, and those lobes are separated by a horizontal fissure and an oblique fissure.

The left lung only has two, the upper and the lower lobes.

How you would remember that? Just remember, because the heart sits mostly on the left side...

Well, it sits on the left side of the, of the body, then you probably would have to have two s-- uh, lungs already or two spaces in there.

So that's one way to think about it.

And then on the right lung, there is a horizontal fissure.

It's almost at the level of, of the heart.

So that's just one tip on how you would remember that, so you won't forget, okay? Left side has something important, and that is what I say the cardiac notch, and that literally is where the heart sits so that the lung has h- its dip or indentation, and that's why the left and right are not identical, okay? Now, the airway pathway, the air comes through the nose, and then we encourage the nose breathing because it humidifies and it conditions the air better than mouth breathing, okay? That's what's happening.

So when you're breathing through the nose, it humidifies the air.

So it goes from the nose down to the trachea and then goes down to the right and the left main bronchi, and then the bronchi.

Then smaller ones would be called bronchioles, and then smaller ones become alveoli.

Now, one of the most classic clinical points, and I still say this to all students, it's about the right main bronchus.

Why is that important? It is shorter, it is a bit wider, and it's more straight and vertical compared to the left, okay? So if something is aspirated or if infection, you know, if it happens, there's infection on the infection tract, then you will often see that it almost always goes to the right side more commonly.

And then, uh, you reach the alveoli, and that's the alveoli is where the gas exchange happens.

Now, pulmonary circulation, which is the gas exchange loop.

So let's connect the lungs to the circulation this time.

So because you need-- This is important for you to know because you need this to make sense of why oxygen numbers change and why people get breathless and why surgery changes the mechanics of these things.

So blood returns from the body via the superior vena cava and then the inferior and ve-- inferior vena cava, okay, to the right atrium, and then from the right atrium down to the right ventricle to the pul-- via the pulmonary artery, okay? And the key point here is that the pulmonary artery is the only artery that carries unoxygenated blood.

Okay, these are some tips for, um, pub quiz, yeah? So the lungs, the blood goes to the lungs, and then gas exchange happens, and the blood returns via the pulmonary veins to the left atrium, then left ventricle, then out to the body as well, right? Key point here is that the pulmonary veins are the only veins that carries oxygenated blood.

Okay? Right.

So, uh, that's enough about the anatomy, and that's anatomy in a nutshell.

All right.