So let’s look at the axillary artery.
Remember, this is
a right shoulder joint. We can see we’ve
got pectoralis minor in a position here.
We can see we’ve got the clavicle. We can see
we’ve got the humerus. And we can see entering
into the axilla is the axillary artery. Over
on this side of the screen, we can see the
first part of the axillary artery as it is passing
deep to the clavicle. And we are going to look
at the branches that are coming from it. So,
the axillary artery can be divided into three
parts. Between the lateral border of the rib
1 and the medial border of pectoralis minor,
we have the first part. And coming away from
the first part is the superior thoracic artery.
So here, we can see the lateral border of rib
1, we can see here. And the medial border
of pectoralis minor, we have the first part
of the axillary artery. And really, coming off
this first part is just going to be one artery.
And this is the superior thoracic artery.
Superior thoracic artery, as its names suggest,
is going to supply the superior aspect of
the chest wall. So it will supply the first
and second intercostal spaces and also give
blood supply to serratus anterior. If we then
carry on passing down through the axilla,
we can follow the axillary artery as it now
runs deep to the pectoralis minor muscle.
And the second part conveniently gives off
two arteries. This is the lateral thoracic
artery. So we have the lateral thoracic artery and
we can just about make that running underneath
pectoralis minor here, the lateral thoracic
artery. And as its name suggests, this supplies
the lateral thoracic wall especially serratus
anteriorly. But also coming from the second
part, posterior to pectoralis minor, is the
thoraco-acromial artery. In the diagram, we
can see it’s just slightly above pectoralis
minor, and that’s really for convenience
or the diagram becomes very confused. We can
see that just above here, but coming from
the second part, we have the thoraco-acromial
artery. The third part, we can see, is coming
from below pectoralis minor. So as the axillary
artery passes below pectoralis minor, this
inferior or lateral border of pectoralis minor,
we can see the axillary artery carries on.
And the axillary artery finishes as it passes
alongside the inferior border of teres major
where it then becomes the brachial artery.
So as the axillary artery passes the inferior
border of teres major, it becomes the brachial
artery. But within these boundaries, the third
part of the axillary artery gives rise to
two circumflex humeral arteries. It gives
rise to anterior and posterior circumflex
humeral arteries. We can see these running
around the surgical neck of the humerus here,
and this will anastomose around the surgical
neck of the humerus. And it also gives rise
to the subscapular artery. And we can see the
subscapular artery running down in this direction.
It’s running down to supply the thoracic
wall, but it also gives rise to the branches
going back up here. And this is known as the
circumflex scapular artery. We can see this
running all the way over here in this direction.
And later on, we’ll see an important anastomosis
of this artery around the scapula. But first
of all, I just want to talk about the thoraco-acromial
artery. This is an artery coming from the
second part of the axillary artery deep to
pectoralis minor. It is a short and wide artery
that pierces the clavipectoral fascia, and
it divides into four important branches.
We can see it’s coming off here. It’s very
short. It’s quite wide, coming from the
second part of the axillary artery. We can
see we’ve got a clavicular branch, and if
you remember looking at the clavicle in the
first lecture, we had that nutrient foramen.
And this is where the clavicular branch passes
in to supply the clavicle. We can see it then
comes away and we have these pectoral branches
that go and supply pectoralis minor and pectoralis
major, the pectoralis muscles on the anterior
chest. And we can see it then turns laterally
and it goes towards the deltoid muscle. It
has a deltoid branch, and it goes up towards
the acromion, the acromial branch where it
can form again numerous anastomosis around
the scapula; so the thoraco-acromial artery
coming off the axillary artery, coming from
its second part. So now, let’s move down into
the arm, and we can see on the diagrams here
on the screen, we’ve got now the brachial artery.
As the axillary artery pass the inferior
border of teres major, it just became the
brachial artery as it run in the brachium
which is your arm. It runs down. And remember,
it’s running alongside or adjacent to the
median nerve, we can see running here. And here, we
can see of a more anterior view close up with some of
the muscles being dissected; we can see the
brachial artery here running alongside the
median nerve. And we can see various muscular
branches going towards brachialis and biceps.