Inthis video I'm going to be talking about the tracheobronchial tree and specifically we're
going to be talking about the names of the lobar and segmental bronchi. It's really important
to know the names of the segmental bronchi and be able to trace them out because it will help
you localize things like tumors or infections, and plus if the patient ever gets radiation or
they have surgery and the anatomy gets distorted, knowing the segmental anatomy will help you figure
out where things are. This is a CT of a normal patient and I'm just going to take you through
the lobar and segmental bronchi. So here we are at the carina. Just to the right of that is the
right mainstem bronchus and if we continue on to the right, that's the right upper lobe bronchus.
It's the first bronchus that comes off of the right mainstem bronchus. So I'm going to scroll
up and there's three segments in the right upper lobe: the apical, the anterior, and the posterior. So,
I'm scrolling up now you can see this one that's a circle it's going to go straight up
to the apex. That is the apical segmental bronchus. Okay I'm going to scroll back down, and this one
that goes anteriorly here is the anterior segmental bronchus. And then I'm just going
to scroll back up a little bit you can see this one going posterior here, this is the posterior
segmental bronchus okay. So we have the apical, the posterior, and the anterior segmental bronchi.
So after the right upper lobe comes off, the next branch is the bronchus intermedius. So there's the
right upper lobe, this is the bronchus intermedius. The bronchus intermedius gives rise to the right
middle lobe bronchus and the right lower lobe bronchus. So if I keep scrolling down, that is the
right middle lobe bronchus and that is the right lower lobe bronchus. Let's take the right middle
lobe bronchus first. The right middle lobe bronchus only has two segments: the medial and the lateral.
So you can see here this one is medial and this one is lateral. Okay, let's scroll back up to the right lower
lobe bronchus again right there, and the first branch off of the right lower lobe bronchus is the
superior segmental bronchus and that's this branch right here. The superior segment of the right lower
lobe is the only one that doesn't touch the right hemidiaphragm. The others are the basilar segments
and those touch the diaphragm. Okay so after the superior segment comes off we have this
bronchus here and this is called the truncus basalis. The truncus basalis is the branch of the
right lower lobe after the superior segment that gives rise to all four of the basilar segments.
And the order in which the basilar segments branch can be remembered with the mnemonic MALP. M as in
Mary. A, L, P. Okay so let's follow this truncus baslis down and see what happens. Okay so,
first we have this branch here and that is the M--the Medial segmental right lower lobe bronchus.
Okay, the next one that comes off is this one and that's the A--the Anterior segmental bronchus. And
then we have a division of this last branch into two branches and that is the L and the P. So this
one that goes lateral this way this is the Lateral segmental bronchus and this one is the Posterior
segmental bronchus. Okay so M, A, L, P. Those are the segmental bronchi on the right side. All right,
now let's look at the bronchi on the left side. So I'm going to scroll back up here up to the carina
Okay so here we are at the carina, and this is the left mainstem bronchus going over to the left. And
this is the left upper lobe. So remember that the left upper lobe is really analogous to the right
upper lobe and the right middle lobe on the right side, because you have two divisions in the left
upper lobe, the superior division and the inferior division. The inferior division is the lingula and
the superior division is made up of two different segments. So let's let's scroll up and we'll look
at those. So on the right side, remember that we have three segments, the
apical, the anterior, and the posterior segments. Well on the left side two of those segments are
combined. So rather than having an apical segment and a posterior segment separate, those two are
combined into one segment on the left side. This is called the apicoposterior segmental bronchus.
Okay if we scroll up we can see that it goes up to the apex and it also supplies the posterior
segment. If we scroll back down, this right here is the anterior segmental bronchus, and if we scroll
further up then we can see that that supplies the anterior part of the superior division of
the left upper lobe. So those two segments, the apicoposterior and the anterior segment make
up the superior division of the left upper lobe. The superior division of the left upper lobe is
analogous to the right upper lobe on the right side. Okay so let's scroll down and we'll talk
about the inferior division which is the lingula. The inferior division, the lingula, is made up
of two segmental bronchi: the superior lingular bronchus and the inferior lingular bronchus.
So this right here is the superior lingular bronchus and it's kind of hard to see on axial
sections but I'm just going to scroll down a couple slices, so this one right here is the
inferior lingular bronchus. Let's take a look at that on coronal images. All right so here we
have coronal images of the same patient and we're just going to take another look at the superior
and inferior lingular bronchus. So this is the left mainstem bronchus and scrolling. H ere is the
superior division and coming forward this is the inferior division. And the inferior division we said
has the superior and inferior lingular bronchus, and that is it right there. So that is the superior
lingular bronchus, and that is the inferior lingular bronchus. And then finally we have
the left lower lobe bronchus. So the left lower lobe bronchus is right there and just like on
the right side the first bronchus that comes off of the left lower lobe is the superior segmental
left lower lobe bronchus. And this is just like the superior segment on the right side in that
it doesn't touch the left hemidiaphragm. Okay, it is not one of the basilar segments, it's the superior
segment. Once the superior segment branches off, then you have the truncus basalis on the
left side. So if you remember we have a mnemonic on the right side to tell us what order the basilar
branches come off. Well on the left side we also have a mnemonic to tell us the order in which the basilar branches come off.
And on the left, its ALP, A, L, P. So A stands for Anteromedial. L is Lateral and P is Posterior.
So on the right side, we had 4, MALP. On the left side we have 3, ALP.
And the 'A' encompasses both the anterior and medial basilar segment whereas those are split up on the right side.
Okay so let's follow the bronchus down. okay so this is the anteromedial basilar segment.
This is the lateral basilar segment. And that is the posterior basilar segment.
Okay, A, L, P. And that's it. So those are all of the segmental and lobar bronchi in the lungs.
Sometimes there can be varying branching patterns, but if you know the segments in each lobe,
then you can pretty much figure out what's going on even if there's a little bit of variance in the anatomy.