This is known as the cruciate anastomosis.
Now let’s move on to the posterior thigh
and the popliteal fossa. First of all, here
we can see we have the posterior thigh.
We can see we’ve got the large sciatic nerve
passing down. And we can also see some of
these perforating arteries that I’ve talked about.
So we can clearly see some of the perforating
arteries passing through adductor magnus.
We’ll come back to them. And then we can
follow now onto the posterior surface of the
knee, the popliteal fossa. We can see the
popliteal fossa running down the posterior
aspect of the knee. And within it, we have
the popliteal artery. So let’s look at the
posterior thigh. First, we have perforating
arteries, three or four, and these come from
profunda femoris. They pierce adductor magnus
and to the posterior compartment of the thigh.
And as they pierce, they typically send superior
and inferior branches to join up with adjacent
perforating arteries. So you can see you’ve
got a perforating artery here. It will send an
ascending branch up. It will send a descending
branch down. Superiorly, we have one coming
down from inferior gluteal. So superiorly,
we have inferior gluteal supplying the more
proximal aspect of these thigh muscles.
And inferiorly, the popliteal artery will pass
up as well to supply the more distal aspect
of these hamstrings. But the main supply is
going to be via these perforating arteries
coming from profunda femoris and passing through
adductor magnus. You can also see that they
will supply the sciatic nerve as they go on.
Here, we have a specific blood vessel to the
sciatic nerve, the artery of the sciatic nerve,
and that is coming from the inferior gluteal.
But more distally, they’ll come from these
perforating arteries. If we now look at the
popliteal artery, it is the direct continuation
of the femoral artery within the popliteal
fossa. So the femoral artery passed through
the adductor canal. It exited the canal via the
hiatus, and it became the popliteal artery.
Here, we can see the popliteal artery within
the popliteal fossa. This popliteal artery
is important. It goes on to supply the leg
and the foot, and it also supplies the knee
joint by way of genicular arteries. So we’ll
come to those in a moment. But first of all,
we can see the popliteal artery terminating
by this anterior and posterior tibial artery.
Here, we’ve got the anterior tibial artery,
and we’ve got the posterior tibial artery.
And this occurs at the inferior border of
popliteus. Here, we can see popliteus muscle,
and we’ve got the inferior border of popliteus
muscle, and that is bifurcating here into
anterior tibial and posterior tibial.
If we look at the popliteal artery itself before
it bifurcates, it gives rise to five genicular
arteries. And these supply the joint capsule
and ligaments of the knee joint. We have two
superior and we have two inferior, and we
differentiate the two superior arteries into
lateral and medial, and the same for the inferior.
So we have superior lateral, superior medial,
inferior lateral, inferior medial. Here, we
can see the popliteal artery giving rise to
the superior lateral and the superior medial
genicular arteries. We can then see them giving
rise to the inferior lateral and inferior
medial genicular arteries. We can see they’re
giving muscular branches that go and supply
the heads of gastrocnemius here. But here,
we can see those four genicular arteries.
We also have what’s known as the middle
genicular artery. The middle genicular artery
is important as it specifically goes in to
supply the joint capsule. And these genicular
arteries form the genicular anastomosis as
they curve round onto the anterior aspect
of the knee to supply the entire knee joints.
They’re also going to receive descending
branches from the femoral and the lateral
circumflex arteries. So we can see here, we
have a descending genicular artery. And that’s
contributing to the genicular anastomosis.
This is important as it provides additional
blood supply if the popliteal artery was to
become compromised in some way. Now let’s