Hello anatomy colleagues this is Dr Alsup and let's discuss the femoral triangle.
So in this learning objective video we will list the boundaries but we will also importantly
describe the contents of the femoral triangle as these are some fairly large structures. They can
be palpable or certain components of them are and they're vitally important to the lower limb.
So the femoral triangle is located in the superior medial thigh region so closely
associated with the groin region close to the abdominal region basically at the superior
portion of the lower limb. And it appears as a triangle a kind of a triangular depression
inferior to the inguinal ligament. So recall that that inguinal ligament is going to be the external
oblique aponeurosis that extends from the ASIS or anterior superior iliac spine
to the pubic tubercle. And the inguinal ligament will serve as the superior boundary of
the femoral triangle. The lateral boundary is the sartorius muscle which extends all the way from
the coxal bone all the way to the tibia in fact this is the longest muscle in the body.
But it will also serve as the lateral boundary of the femoral triangle. The adductor longus is going
to be the medial boundary one of the muscles of the medial or adductor compartment and the floor
of the femoral triangle rests on two deeper muscles of the anterior thigh region. You'll
have the iliopsoas as well as, the iliopsoas is going to be kind of more laterally placed, and
the pectineus will be more medially placed. It's not quite as visible here because it's being
blocked by the contents of the femoral triangle. So let's talk a little bit more about those contents.
There are three major neurovascular structures that are contained within the femoral triangle,
but the medial most portion of the femoral triangle actually contains the femoral canal
which is in this basic region right here.
Really the femoral canal is a small area mainly containing adipose tissue
but it does have some but not all of the deep inguinal lymph nodes.
Continuing to move from medial to lateral we get to the bigger structures starting with the
femoral vein. The femoral vein is the continuation of the popliteal vein so both are considered
deep veins even though at this level the femoral vein is very superficially located.
The femoral vein will become the external iliac vein past the inguinal ligament. The femoral artery
is going to be just lateral to the femoral vein. This artery is the continuation of the external
iliac artery excuse me past the inguinal ligament and is the dominant supply to the lower limb. And
it actually gives off its largest branch the deep artery of the thigh within the inguinal triangle.
The most lateral structure, large structure, is going to be the femoral nerve which is the
largest branch of the lumbar plexus and will be the dominant supply to the anterior thigh
as well as having cutaneous innervation supply in a multitude of areas and we'll
talk about that in more detail in upcoming sessions. And it will give off numerous
branches within the femoral triangle as this is kind of trying to represent here.
I often remember the order of these structures through the the mnemonic VAN which tells you from
medial to lateral, so this is from medial to lateral, the order of the structures of those
largest neurovascular structures so vein artery nerve. You may see in some of your
study guides like first aid the mnemonic NAVEL which goes into a bit more detail
but it's kind of in the reverse so it's going from lateral to medial so lateral to medial.
And what this is, the mnemonic is indicating that the nerve is the most lateral
artery is next, vein, then it's talking about the empty space associated with the femoral canal,
and then the lymphatics are going to be the the L so that's what the naval mnemonic is getting at.
So a few things I want us to consider about this area, and these are reasons that this
area is often discussed. First and probably most importantly the pulsations of the femoral artery
are palpable within the triangle due to its relatively superficial position deep to the deep
fascia. And this can be useful for a multitude of reasons including first of all getting a
femoral pulse. But also since the femoral vein is not typically palpable even here, knowing the
relationships or that geographic relationship of the femoral triangle can help one understand
where the femoral vein is as well, so it's going to be just medial to the femoral artery. And that can
be important in getting blood samples, taking pressure recordings, femoral vein cannulation,
those are a few things that where that could be useful. Additionally I want to
note that the femoral artery and vein as well as the femoral canal are going to be
wrapped up in what is referred to as the femoral sheath. And this sheath is pretty robust,
it will actually extend deep to the inguinal canal allowing that femoral vasculature to
glide deep to the inguinal ligament particularly during movements of the hip joint. Often during
dissection it is difficult to differentiate between the artery and the vein because it
is so tightly wrapped that they are both so tightly wrapped together in this femoral sheath.
Lastly at the base of the femoral canal you'll have this area which I'm circling here
that's referred to as the femoral ring, it's an oval ring-like shape. It's a relatively weak area
associated with the inguinal triangle region and it's most typically the originating site
of a femoral hernia. So it is at this femoral ring like right here at the base of the femoral canal
that you most commonly have femoral hernias, which is a herniation or protrusion of abdominal viscera
through the femoral ring and into the femoral canal. It is observable, if it is observable, it
will be present as kind of a small bulge in the medial femoral triangle region.
The herniation as you can imagine can compress the other contents of the femoral canal.
So a small but important area of the anterior superior limb.
Please take time to review the boundaries and contents and reach out if you have any
forms of any questions. Thank you for your time and attention