00:01
So, let's start by having a look at the axillary artery.
00:05
So, the axillary artery really is the direct
continuation of the subclavian artery.
00:10
Here, you could see the subclavian artery passing
out of the brachiocephalic trunk from the heart.
00:15
And in this case, it's coursing towards the
right-hand side where it enters into the axilla.
00:22
Here, we can see the lateral margin of the first rib is the landmark
where the subclavian then becomes the axillary artery.
00:29
The axillary artery then, runs through the axilla and at the
lower border of teres major, it becomes the brachial artery.
00:37
Using the pectoralis minor muscle as an important landmark,
this can separate the axillary artery into three parts.
00:44
The first part is situated between the superior
boundary of pectoralis minor
and the clavicle where it's coming
from the subclavian artery.
00:53
Here, we can see the second part which
is deep to the pectoralis minor muscle.
00:57
The third part of the axillary artery is really appearing
between the inferior border of pectoralis minor muscle
and the inferior border
of teres major muscle.
01:08
And this is where we find the
third part of the axillary artery.
01:12
There are a number of arteries that
come off these respective parts.
01:15
So, coming from the first part of the axillary artery,
we have the superior thoracic artery.
01:20
Coming from the second part of the axillary artery,
we have the thoraco-acromial artery.
01:26
We also have the lateral thoracic artery that
passes down the lateral aspects of the thoracic cage.
01:32
And then, moving to the third part of the axillary
artery, we have the subscapular artery.
01:37
And then, importantly, we have both the anterior
and posterior circumflex humeral arteries.
01:44
And these go around the surgical neck of the humerus.
Dislocation of the humeral head, so, the head of the humerus
if it becomes dislocated can actually
start compressing onto the axillary artery.
01:57
So, it can jam the axillary artery
between the dislodged humeral head
against the first rib and the
lateral wall of the rib cage.
02:06
And this can lead to occlusion
of that blood vessel,
preventing blood from passing
distally towards the upper limb.
02:13
If we then look at the thoraco-acromial
arteries specifically,
we have an acromial branch that goes to supply
regions around the acromion and the joint,
the clavicular acromial
joint for example.
02:23
And we also have a clavicular branch
that goes on to supply the clavicle.
02:27
We have a pectoral branch that supplies the
pectoralis muscles, so, pectoralis minor, pectoralis major.
02:33
And we also have another branch supplying
the mass muscle which is the deltoid muscle,
forming the real shape of the shoulder
that we can see in the living person.
02:43
So, we have a deltoid branch coming off
the thoraco-acromial artery.
02:48
This is a really important artery that supplies
lots of things around the shoulder joint.
02:52
It also gives rise to that lateral thoracic artery
which we can see passing down
on the lateral aspect of the thoracic cage.
Here, we can see it passing down here.
03:02
So, we have a lateral thoracic artery which we
can see here, supplying serratus anterior muscle.
03:08
We can also find the subscapular muscle.
03:11
So, the subscapular muscle is going to work
its way posteriorly to supply subscapularis muscle.
03:16
And here, we can see it doing so as it courses
towards the scapular, supplying subscapularis,
the muscle on the anterior
surface of the scapula.
03:26
We can see it gives rise to the thoracodorsal
artery which we can see here.
03:30
And we have various other named
branches, the circumflex scapular artery.
03:34
And that's passing through the triangular space
as that space that allows structures to leave the axilla
and pass through the posterior
aspect of the shoulder region.
03:44
Here, we could now see the circumflex scapular
artery passing up along the posterior surface
of the scapula humeral muscles.
We can see it running up infraspinatus.
03:55
The dorsal branch of the dorsal scapular
artery is an important branch
that comes down to join that circumflex scapular
artery and here, we have an important anastomosis.
04:05
Helping when we spoke previously about axillary
artery being occluded, perhaps, due to dislocation.
04:11
It means that use these anastomosis, blood
can still reach this region by an alternative root.
04:16
So, these anastomosis
can be important.
04:19
Another important anastomosis that we need to be
aware of is around the circumflex humeral arteries.
04:24
Both the anterior and posterior branches run around the
surgical neck where they form this important anastomosis.
04:32
So, here, you can see the surgical neck
of the humerus and the posterior
and anterior circumflex humeral arteries are
converging to form that anastomosis around this region.
04:43
Remember that the posterior circumflex
humeral artery leaves the axilla
by passing through the quadrangular space.