00:01
So let’s look at these spaces
a little bit more detail. Here, we’re going
to look at the quadrangular space. And the
quadrangular space is important because it
contains the axillary nerve. The axillary
nerve, as we remember, innervates the deltoid
muscle and it’s coming away from the brachial
plexus, which is located within the axilla.
00:21
So the axillary nerve comes from the brachial
plexus within the axilla and it passes out
towards deltoid muscle by passing through
the quadrangular space. Also coming through
this space, we have the posterior humeral
circumflex artery and accompanying vein, and
these run around the surgical neck of the
humerus. So what makes up the boundaries of
this quadrangular space? Well, on the screen
at the moment, we can see an anterior view
of the right shoulder. So we can see the chest
wall has been removed and we can see here
we’ve got subscapularis muscle, and then
down here, we can see we’ve got the humerus
and various muscles. We'd remind ourselves
that we’ve got teres major muscle running
up here. So, what we can see is if we look
at the quadrangular space, it’s going to
be this muscle in here, the quadrangular space.
We’re going to see this muscle in here.
01:22
We can see that inferiorly, we’re going
to have a muscle. Inferiorly, we’re going
to have a muscle and that is teres major.
We can see teres major running here.
01:33
We can also see that if we go medially, we can see
we’ve got a muscle here, and this muscle
is the long head of triceps. We can see that
here. If we look laterally, then we can see
we actually got the humerus here, and this is
going to be the surgical neck of the humerus.
01:51
Superiorly, teres minor is quite difficult
to see actually because subscapularis muscle
is in the way. But we’d have teres minor
running across in this direction.
02:03
Remember, teres minor comes away from the scapula
superior to teres major. So here, we can see this small
little space. Superiorly, we’ve had teres
minor. Medially, we’d have the long head
of triceps brachii. Inferiorly here, we’d
have teres major. And laterally, we'd have the
surgical neck of the humerus. And this is
your quadrangular space. Coming through that
space is going to be the axillary nerve and
the posterior humeral circumflex artery and
vein. If we move on to the next slide, we can
actually see if we just remember the quadrangular
space. We can pick it up again here. And now,
we can see that superior boundaries, teres
minor. So in this posterior view of the right
shoulder, again, we can see superiorly now
we have teres minor; inferiorly, we have teres
major; laterally, we have the surgical neck
of the humerus; and medially, we have triceps
brachii, the long head. And again, we can see
the quadrangular space. But this slide,
I want to talk about another space, and this
space is known as the triangular space. And we
can see the triangular space here. The triangular
space is important as it allows the circumflex
scapula vessels to pass out from the axilla
and go to supply the scapula region. It has
got three boundaries. That’s why it’s
called the triangular space. And those three
boundaries are superiorly, teres minor; inferiorly,
teres major; and laterally, we’ve now got
the long head of triceps again. So we can see
that triceps, the long head of triceps is
forming the medial boundary of the quadrangular
space and it’s forming the lateral boundary
of the triangular space; the medial boundary
of the quadrangular space, the lateral boundary
of the triangular space. With teres minor
running across superiorly for both of these
spaces, and teres major running inferiorly
for both of these spaces. So being aware of
the musculature of the axilla, what forms
its boundaries, helps us to appreciate the
boundaries of these spaces. So this is the
triangular space. The final space I want to
talk about is known as the triangular interval.
04:35
And this is important as it allows structures
to pass out of the axilla and pass to the
posterior compartment of the arm to supply
the triceps muscles. We have the radial nerve
and we have the profunda brachii artery. Now,
this is slightly harder to see because the
space is actually closed here. But what we
can see again is superiorly, we’ve got teres
major, and the space is actually going to
sit in between the humerus and the triceps
long head. So here we can see we've got triceps long
head, we've got the humerus, and then superiorly,
we've got teres major. And just in this little
interval, this little slit here, we find the
triangular interval. And coming out of here,
we have the radial nerve and the profunda
brachii artery. So this is not as clear as
the quadrangular and the triangular, but here,
just in this little slit here, superiorly,
teres major; laterally, the humerus; medially,
the long head of triceps brachii, we have
the triangular interval. So, very important
spaces that allows structures to pass out
of the axilla to the wider areas.