So that leads us then to an understanding of the coronary circulation.
The heart as you might imagine, has an intense metabolic need for nutrients and for oxygen,
and there are two arteries that will help supply the heart with arterial blood.
At rest, about 225mm per minute of blood is being delivered to the heart
through the right coronary artery and through the left coronary artery.
Again, coronary means crown and these arteries will form a crown around the heart itself
and then issue numerous branches.
If we take a look at this view, we can see our right coronary artery
traveling then within the coronary sulcus or atrioventricular sulcus.
It will wrap around to the posterior diaphragmatic area of the heart and still will travel within the coronary sulcus,
and we can see some branches issuing from the right coronary here, in this view,
and then along the right margin of the heart we see a marginal artery issuing from the right coronary.
The left coronary artery, we see here, it's gonna issue from the aorta,
right above the left coronary semilunar cusp, it's traveling posterior to the pulmonary trunk
and underneath the left auricle, so the left auricle bridges over the left coronary artery.
The left coronary artery at first is a very short segment and then it's gonna issue its two branches.
The one that travels in the anterior interventricular sulcus is referred to as the anterior interventricular artery,
and then the other one that we see here is going around within the coronary sulcus
but it's wrapping around the left side of the heart traveling within the coronary sulcus,
and as it wraps around it, this one is called the circumflex artery.
When we take a look at the coronary arteries, there is a dominance or dominant pattern that can be determined
and if we take a look here, we have our right coronary artery
and if we follow our right coronary artery within the coronary sulcus,
and see it wrap around the right side of the heart as we do here,
we will see that the right coronary artery will dive down into
and travel within the posterior interventricular sulcus.
When the right coronary artery gives rise to the posterior interventricular artery
that travels in this posterior interventricular sulcus, this is called a right dominant pattern.
The majority of individuals have a right dominant system.
The percentage will vary from one study to another so it might be 70%, 80%,
or maybe a little bit higher than that in frequency.
And here we're looking at the opposite dominant pattern and if we take a look at what's going on here,
we will see our left coronary artery, we see the anterior interventricular artery
traveling in the anterior interventricular sulcus which is normal.
Another name for our anterior interventricular artery is our left anterior descending artery
or the acronym, LAD and LAD is commonly used in the medical profession.
The circumflex artery is issuing right at this point and if we follow it around the left margin of the heart,
to the diaphragmatic view, posterior view, we see it also traveling in the coronary sulcus,
and if we follow it distally, we see it dives down into the posterior interventricular sulcus,
thereby continuing as the posterior interventricular artery.
And when it's the left, in this case the circumflex that gives rise to the posterior interventricular artery,
you'll wanna call this a left dominant pattern.
This is the second most frequent pattern that we'll see,
however, it is usually somewhere around 8%-10% in frequency.
The last pattern that can be seen as a variant is a balance pattern.
In a balance pattern what happens is we end up with two posterior interventricular arteries.
One coming from the right coronary artery and then if we could move this one over here,
more in line here and running parallel to the one coming from the right,
we have two more clearly define discernable posterior interventricular arteries that is a balanced pattern,
and of the three this one is the least frequent pattern that we'll see.
Here we have a superior view of the coronary arteries. Here is the aorta cut in cross section.
Here is your right coronary cusp or right cusp and here you can see the ostium leading into the right coronary artery.
The right coronary artery in a dominant pattern is gonna supply
primarily the right side of the heart, right ventricle, right atrium.
Also will supply important structures of the conduction pathway,
the SA node and we can see the artery, right here, leading to the SA node
and it will also issue posteriorly here most commonly an artery to the atrioventricular node
also helps supply the interventricular septum.
Here is the left coronary artery, ostium is right here, right above the left coronary cusp
and again very short, here you can see it continuing as it enter your interventricular artery or the LAD.
This is the one that's most frequently blocked leading to a myocardial infarction
and it can lead to death, and so it's also referred to as the widow maker,
and then here's your circumflex wrapping around as we see here.
Here's your posterior interventricular artery and give you a moment to think about it,
which coronary artery is given rise to the posterior interventricular artery
and the answer is it's the right one coming around diving down
into the posterior interventricular sulcus, so this is a right dominant pattern.
The left, in this case is supplying mainly the left ventricle, left atrium, interventricular septum.
Like any other organ that's receiving a blood supply,
the heart also have structures in place that will help drain the organ of venous blood,
so we do have a system of veins to do that.
The main veins to keep in mind here as a learner that would be the great cardiac vein,
the middle cardiac vein and the anterior cardiac veins.
Here in this view, sternocostal anterior view, we can see the first vein and the last bulleted veins.
So traveling here, in the anterior interventricular sulcus, out with the anterior interventricular artery or the LAD,
is its accompanying vein and blood is flowing upwards here in this system,
this is called the great cardiac vein and it's gonna dive into the coronary sulcus
wrapped around the left margin of the heart and empty into a structure
that we call the coronary sinus, a co-acting system.
We can also see here on the right ventricular side, we see in this case three anterior cardiac veins.
They're draining in the right ventricle primarily venous blood
and they empty directly into the right atrium so they are very small ostia or openings here into the right atrium.
The next slide will help us to understand some of the additional veins
and also see what we saw on the anterior view, wrapping around here to the posterior view
and so what we'll want to focus on here is for a reference is the great cardiac vein coming up
and around to empty into the coronary sinus.
Coronary sinus will receive most of the venous blood flow being drained from the heart,
separate opening, large opening into the right atrium that we saw in an earlier slide
when we looked at the internal anatomy of the right atrium.
We also have here accompanying the posterior interventricular artery,
we have its vein, this is called the middle cardiac vein.
It drains blood also into the coronary sinus advance into the right atrium.
We also has some smaller veins that will empty into the coronary sinus
so the coronary sinus drains most of the heart of venous blood.
Anterior cardiac veins are gonna drain primarily the right ventricle
and the last system of veins that we have, we cannot see in this view,
they run deep within the muscle tissue itself and drain into the cardiac chambers
and these are the venae cordis minimae.