hi let's talk about the coronary arteries the coronary arteries are and their branches are the
direct source of blood to the myocardium of the heart they are branches of the ascending aorta so
the ascending aorta is coming off of the right ventricle and there is a left coronary artery
usually referred to as the lca and a right coronary artery usually referred to as the r ca
they take their origins in the aortic sinuses also known as the sinuses of valsalva
with the lca coming from the left sinus and the rca coming from the right sinus if we look at
this illustration so this is posterior and this is anterior i'm just going to outline the ascending
aorta there and we can see the the cusps of the aortic valve here is the right
aortic sinus and here is the rca here is the left
sinus and there is the lca and you can see that the lca kind of rubs up against
the the pulmonary trunk there before ramifying into the anterior interventricular
artery and the circumflex branch now both the lca and the rca
are going to travel along the coronary sulcus
so on on this particular heart this is kind of a an odd view of it so there's the inferior margin
of the heart there is the apex there there is the anterior interventricular sulcus the pulmonary
trunk has been reflected down and away there's part of the coronary sulcus there's the other
part of the coronary sulcus so let's look at the the branches of the rca and then the branches of
the lca so here is another anterior view of the heart so inferior border right border
left border apex we can see it leaving the ascending aorta so
there's the origin of the r ca and immediately it gives off
the sa nodal branch and this is usually about you know six and ten incidents that the
sandal branch going to the sino-atrial node will come off of the rca and the remainder of instances
it's typically a branch of the lca so that rca is then going to continue down through the
coronary sulcus and you can see it's giving off a couple of branches
along the way there's one there's another and then towards the uh that inferior border it's going to
give off the right marginal branch and that right marginal branch rides the inferior border of the
heart toward the apex so that's really going to supply the wall of the right ventricle with blood
then the rca remaining in the coronary sulcus let's flip this
around so here is the coronary sulcus that's precisely where we left off here is the
diaphragmatic surface of the heart here is the coronary sulcus moving across here is the
posterior interventricular sulcus there we can see the rca
continuing to move across there is the right marginal branch
heading that way and the rca continues on to this region which is known as the crux of the heart
the crux of the heart is where the coronary sulcus meets the posterior interventricular sulcus
and this is going to be significant because
whichever vessel whether it's the rca or the lca that makes it to the crux of the heart
is typically going to supply blood to the posterior interventricular branch
and the av nodal branch the av nodal branch is supplying blood to the atrioventricular node
the posterior interventricular branch is supplying blood to the interventricular
septum so a large portion of the wall of both ventricles and it's an important portion of the
walls of the ventricles because it's conducting the the bundle branches down from the uh
the bundle of his now this is an example of a right dominant heart because the rca
is the only blood supply to the crux of the heart there but there are also left
dominant hearts where the lca makes it and is the exclusive source to the crux and then there
are codominant hearts where both rca and lca will supply the crux of the heart with blood
now the left coronary artery arises in the left coronary sinus of valsalva and it ramifies
into the anterior interventricular branch that comes down that anterior interventricular
sulcus this anterior interventricular branch is often known as the lda or the left descending
artery and that's supplying blood to the walls of here the the left ventricle as well as the
interventricular septum the other branch is the circumflex branch which stays within the coronary
sulcus and then gives rise to the left marginal artery that left marginal artery is coming down
along the left border of the heart and then that circumflex branch will have a variable course
on the in the coronary sulcus on the diaphragmatic surface of the heart sometimes it gets to the crux
in a minority of cases most of the times it does not get there so bringing our attention
back to this or photograph where posterior is there and anterior is there i i want us to
to look at the rca one more time we can see it following the sulcus and we can
see it getting to the crux here so it's giving rise to that posterior interventricular branch
as well as the av nodal branch which we can see here going to the atrioventricular node so those
are the coronary arteries left and right and their various branches thank you very much for your time