Hello anatomy friends this is Dr Alsup and in this video we will be discussing the major joints
that we need to in the knee as well as the distal lower limb session.
This will likely be our longest video as we have quite a few joints to discuss and two of
these joints are a bit more complex than many of the others we have discussed throughout our time.
So much to do so let's get started and we will start with the knee joint and the knee joint
pretty similar to the shoulder joint is brought up quite a bit in our discussions due to the numerous
things that can go wrong in this area. Now recall that the fit between the articulating bones of
the knee joint is not a particularly tight fit so you have these relatively large femoral condyles
that are sitting on and articulating with these relatively shallow tibial condyles, you do have the
menisci here that we'll talk about in a moment, but just the point is that the fit between the bones
it's not particularly tight so ligaments and tendons play a huge role in maintaining the
stability of this region. One thing to note the anterior portion of the articular capsule of
the knee joint is thin and often incomplete, but not to worry because we have the complex
of the quadriceps femoris tendon which is a major protector of the anterior portion
of the knee joint. So you can see so here's your quadriceps muscle so quadriceps femoris muscle
and you can see the muscle belly is kind of coming together and you have the shared tendon
referred to as the quadriceps femoris tendon, it's any of this kind of white opaque area,
and then forming within the tendon you will have the patella which you can't see quite here because
it's very within that tendon so you'll have the patella that is formed within the tendon.
And the portion of the quadriceps femoris tendon that extends from the patella to
the tibial tuberosity which is you know right about in this area is going to be referred to as
the patellar ligament. And sometimes this whole tendon is referred to as the patellar ligament
but it's really the name change really occurs because you have kind of a connection between
bone to bone so between the patella to the tibial tuberosity would be the ligament portion.
But really it's this whole complex it's continuous and it is formed by the tendon of the quadriceps
femoris so very very important in terms of anterior protection of the knee joint you
can see it here's the patella right here you can see the tendon and the patellar ligament
that has been reflected in order to see some of these deeper structures here.
So let's talk about what else we can see in this particular image with the patella again
and the quadriceps femoris tendon and patellar ligament reflected and this is an anterior view.
We know this is anterior so the anterior view we know this is anterior because you can see
the patella here and it's been reflected and you can only see the patella from an anterior view and
also you can see the patellar surface of the femur which is also only visible from an anterior view.
And you can see quite a bit going on within the the joint region. Looking right into the
joint region you can clearly see the anterior cruciate ligament or your ACL
and it is actually occluding the view of the posterior cruciate ligament that we will
see in an upcoming slide but since this is an anterior view the main thing that you would see
right here in the middle of the joint would be the ACL.
As with many of the joints we have discussed there are collateral ligaments flanking
the sides of the joint and their names make absolute sense. You have the tibial collateral
ligament sometimes referred to as the medial collateral ligament so you'll hear TCL or MCL
and both those names are very descriptive in showing you that it attaches to the tibia
and it is medial. This ligament is a bit wider and really capsular looking meaning that it looks like
a thickening of the articular capsule because it is and it is attached to the medial meniscus which
is difficult to differentiate here but would be sitting on the medial condyle of the tibia
so the medial condyle of the tibia so this would be the medial meniscus. And this is actually these
two structures the tibial collateral ligament and the medial meniscus are attached to one another so
that is important because you have an injury to one you often have an injury to the other.
On the lateral side this is the fibular collateral ligament sometimes referred to as the lateral
collateral ligament, both are very descriptive of where it is located.
And it is completely separated from the articular capsule so obviously close to it but it is not a
thickening of the capsule it looks like a short rope on this lateral side and because it's not
attached to the capsule it also means it is not attached to the lateral meniscus which you can see
pretty clearly here sitting on the lateral condyle of the tibia so this is the lateral meniscus.
Now let's identify many of those same structures but from a posterior view this time and I know
this is a posterior view because I can really see the femoral condyles much better here so you can
see the bulbous portion of the femoral condyles. I can also see a bit of the quadriceps muscle
sitting anteriorly here. So let's focus in on the cruciate ligaments and you can see both
from this view. The one that is most dominant in this view and you can see the entirety of
is the posterior cruciate ligament or the PCL and I know that this is the PCL because it
makes sense it's that you can see the entirety of it because we're looking at a posterior view.
But you can actually see some of the ACL from this view as well
shaded here in pink so this is the ACL and you can appreciate really appreciate
how these are crossed over one another thus their names the cruciate ligaments.
To better understand what these other structures are I first want to understand which side
is lateral and which is medial and the easiest way for me to do this is to look at the bones of the
leg here. Recall that the fibula and you can see the fibular head right here is going to be lateral
and the large tibia is going to be medial so this is going to be the lateral side of the joint and
this will be the medial side of the joint, making this the tibial or medial collateral ligament
and you can see really well how it's attached to the medial meniscus here,
shaded here in green. And then laterally you have the lateral collateral ligament or the
fibular collateral ligament shaded in yellow and it is separated from the lateral meniscus
it's shaded here in this light blue.
Moving distally towards the ankle region and there's much going on here so more than just the
ankle joint. You do have just superior to the ankle joint the distal tibiofibular joint and I'm going
to kind of circle the general region where it's located you obviously have ligaments associated
with those regions. So just superior to the ankle joint is the distal tibiofibular joint and this is
the most distal of the three articulation sites between the tibia and the fibula.
This is actually a fibrous joint so it's not synovial meaning that there's not a tremendous
amount of movement here but we do bring it up because it's a joint in this region but if
you have any damage to ligaments and structures associated with the inferior tibiofibular joint
it's often referred to as a high ankle sprain. The true ankle joint or talocrural joint is formed by
the articulation of the distal and inferior portions of the tibia as well as the fibula
and the talus or the talus which is the most superior of the tarsal bone so it's this complex
right here that is going to be the ankle joint, or what we think of when we think of the ankle joint.
The ankle like the knee joint is a hinge joint and has ligaments flanking the medial
and lateral sides of the joint but instead of being one solid ligament like we have with most
collateral ligaments they're actually ligament complexes on each side so multiple ligaments
associated with each side of the joint. On the medial side these are the medial or deltoid
ligaments and we are not having you identify the separate parts of these ligaments or the different
names of the ligaments but I do want to note that all of these ligaments have an attachment on the
medial malleolus or malleolus of the tibia and not only do they all attach there but they also
interweave together to really form a solid protection on this medial side of the joint.
That's not really the case in terms of the lateral side, now it's true all the ligaments
of the lateral ligaments attach proximally to the lateral malleolus of the fibula which you can see
here what I just outlined. But those ligaments do not interweave the same way that we had on
the medial side so the lateral ligaments tend to be weaker and more prone to injury.
In fact we do want you to be able to identify one of these lateral ligaments which is the anterior
talofibular ligament or ATFL. And it is going to connect the talus
and the fibula at that lateral malleolus so it's shaded here in orange and the reason that we want
you to be able to identify this particular ligament is because it is the most commonly
injured of the ligaments of the ankle so this one is one that we want you to be able to identify.
Lastly I want to touch on two of the more important intertarsal joints so a joint formed between tarsal bones
and we highlight these two joints as they play an important role in allowing the
actions of inversion and eversion of the foot. And these are the subtalar joint
primarily as well as the transverse tarsal joint. The subtalar joint is located at the articulation
between the talus or the talus and the calcaneus so basically where the talus
or talus you hear that either way you'll hear me say it either way just so you're used to that,
it's basically where the the talus sits on the calcaneus or the heel bone so that articulation
site. The transverse tarsal joint is actually a complex joint so two separate intertarsal joints
located in the same plane so it'll be between the talus and the navicular right here, so here's the
talus you don't have to memorize this bone here but it's one of your tarsal bones the navicular,
as well as between the calcaneus which is deep here and the cuboid, so calcaneus and you don't
have to know the cuboid but just being aware that it's going to be right there. So an essence between
the two largest tarsal bones the ones that we want you to be able to identify and some
of the more distal tarsal bone so it is right here that we have that transverse tarsal joint.
All right excellent thank you for your time and attention as we discuss the structures
associated with the knee and joints in the ankle region. Please take time to review and as
always please feel free to reach out with any questions. Have a great rest of your day