Let's cut it in a
slightly different way.
So this is a 4-chamber view,
this is often the view that
you will see on echocardiograms
when you become
This is a 4-chamber view, and we're
looking at the anterior half of the heart.
So it's as if I cut myself
this way through the heart.
And then I took off the anterior
surface, and I presented it to you.
So the anterior surface
of the heart here
is showing you the right ventricle
and the left ventricle as shown.
We have the interventricular
septum in between.
The structure up there at the
top is the tricuspid valve.
So that is bringing blood from the
right atrium into the right ventricle.
And on the left hand
side is the mitral valve,
bringing blood from the left
atrium into the left ventricle.
Let's look at a slightly
yet again, this is so that
we can evaluate the valves
and the circulation.
So this is looking down at the top
of the heart on the right hand side.
And if we are looking down
at the top of the heart,
and we've cut off
most of the vessels,
we are looking at anteriorly
the pulmonary artery.
In fact, the pulmonary artery is the most
anterior great vessel coming off the heart.
Right behind it is the aorta.
Okay, and the aortic valve.
Now coming off the aortic valve is
going to be the coronary arteries.
That's the right coronary
artery, left coronary artery.
They're called coronaries,
because someone thought the way that they
look sitting off the top of the heart,
they look like your crown.
So that's where the name
'corona', coronary came from.
The left coronary artery,
the left main coronary artery
branches into the left
and to the left
And you can see that the
vessels that are going to be
the major epicardial
coronary artery vessels
are coming off the aorta on either
side of the pulmonary artery.
so we're going to do a video here,
looking at the various vessels and
how they course around the heart
and go to the various
parts of the architecture.
We're going to emphasize again
looking from base to apex,
so base at the top,
apex at the bottom.
First vessel that we
see highlighted here
is going to be the left main coronary
artery coming off the left coronary os
that's going to turn
into the left circumflex
as well as the left
Highlighted here is the
right coronary artery,
it's going to come off
the right coronary os
and course underneath the
right atrial appendage,
and you can see it as it winds its
way around to the back of the heart,
in the vast majority of us 90%,
it's going to perfuse the
posterior descending artery.
So that means that we are kind of
perfusing the majority of the heart
of the right ventricle in the posterior
wall off the right coronary artery.
We can also see that there is a marginal
branch that also got highlighted.
Now we're going to come back look
at the left main coronary artery
that is getting
That left main coronary artery is
going to branch relatively quickly
into the left anterior descending
and the left circumflex artery.
And you see highlighted here,
the left circumflex artery that courses
underneath the left atrial appendage,
and winds its way around laterally
on to the left side of the heart.
This is going to be
responsible for perfusing
the lateral wall of the
There are going to be
a number of vessels
that branch off that—
those are the marginals.
Now we're looking at the
left anterior descending
the branches to come off
it are the diagonals.
And as we tip up onto
the apex of the heart,
you can see how the
left anterior descending
and the right coronary artery meet down
there at the apex- a watershed zone.
We're looking now at the left circumflex and its marginal
and there will be
the diagonal branches
that are coming off the
left anterior descending.
Between the left circumflex
and the right coronary artery
is another watershed zone.
And this on the kind of posterior
lateral aspect of the left ventricle
is another zone where
between the right and
the left circulation.