So now we're going to make our way towards the thigh and lower leg, starting with the anterior thigh, looking at the superficial muscles that you're going to see on the cat and then kind of work our way deep. As far as what we see on the cat first, there are two large broad muscles that are pretty much covering everything on the anterior thigh of the cat. So these are the ones we're going to name first. The first one is going to be on the lateral aspect of the thigh.
This is the sartorius, so the sartorius muscle, band-like muscle. Again, notice very broad, covers everything on the cat. In the human anatomy, It's a very thin muscle.
You can see the underlying muscles with the sartorius in place for the human but not on the cat. Now as far as the action of the sartorius, this is a muscle that's going to laterally rotate the knee as well as help with knee flexion. That is our sartorius.
As we go now towards the medial aspect here again, a very broad superficial muscle that we see here is the gracilis. So gracilis again on the medial aspect. This muscle extends and attaches to the knee here so it will help with knee flexion as well.
So those are a few of the actions for these muscles. As we go deep to these muscles on the cat, we're going to reflect them back and we're going to start with the muscles that are deep to the sartorius. So the first muscle that you can kind of see hanging out here deep to that sartorius is this small muscle here that's attached to this aponeurosis.
This is the... Tensore fasciae latae muscle. Tensore fasciae latae muscle with the IT band or iliotibial tract attached to it. So this epineurosis makes its way down to the knee and pretty much helps to stabilize the thigh when the muscle contracts.
Just kind of strains that knee out and puts a little pressure on the thigh here. Stabilizes the thigh. So that's our tensore fasciae latae.
Once we go deep to this, here we now see the quadriceps group. So based on the name we can see that there are going to be four muscles here. We're going to start with the large muscle in the center.
This is going to be the rectus femoris. Rectus femoris muscle. As we go lateral to the rectus femoris we have the vastus lateralis.
This is lateralis there. As we go medial to the rectus femoris here's your vastus medialis. And we've cut these muscles so that we can see the deepest muscle of this group.
So as we reflect the rectus femoris here deep, we see the vastus intermedius. So rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. And these are the quadriceps group.
Now for the actions, this is the muscle group that's going to be responsible for extending the knee, so straightening the lower leg out. But it also will function to flex the trunk, so it aids in trunk. flexion but I think knee extension first I think is probably the easier action too.
So that is the quadriceps group. As we now make our way towards the medial aspect on the cat this can be a little confusing because there are several muscles that are visible here and not all of these muscles are technically muscles that are acting on this anterior aspect. So the first two I want to point out are these two muscles here that actually belong to the hamstring group.
So this is going to be the semitendinosus and this is the semimembranosus. So you're going to see them there from this view. Again, you really don't want to name the actions. They're there, but we're going to ignore them for now. We're going to make our way up and start with this large kind of triangular-shaped muscle that's visible here.
This is going to be, in the cat, the adductor femoris. Adductor femoris. Technically, this is a muscle that humans don't have.
In the human, I want you to consider the adductor magnus. The actions will be similar. They basically adduct the thigh. So they bring that thigh closer to the midline. Along with the adductor magnus in the human, you do have the adductor longus, which is visible here on the cat.
And just like the adductor magnus, this would also adduct the thigh and medially rotate the femur. And finally, one last adductor muscle that's going to have basically the same action is this deep muscle that we see here medial to the blood vessels. You can notice the blood vessels here.
You have this small muscle here. This is the pectineus. So just like the adductor longus, the pectineus would also adduct the thigh.
So again, that's pectineus, adductor longus, adductor femoris and cat, adductor magnus and the human. One last muscle to consider here. We're going to go now lateral to the blood vessels and very deep.
So again, lateral and deep. Notice here's part of the branch of the femoral nerve. As we go deep to that.
We see this kind of cord-like muscle here. This is the iliopsoas muscle. Iliasois. You can say it Iliopsois for the sake of spelling.
There's a P there that's going to be silent. But this muscle as far as the action is going to help flex the thigh. So it's going to pull up on the thigh and can help with trunk flexion as well. So this is the main muscle that will flex that thigh. Along with the quadriceps.
So these are the muscles that we see along the anterior thigh. As we make our way towards the lower leg first and then eventually come back towards the posterior thigh. Moving down to the crural region here, there are five muscles that are going to be easily seen on the cat.
That, of course, will be seen on the human as well. The first one is the large superficial muscle of the calf. This is the gastrocnemius. So the gastrocnemius muscle.
Now the gastrocnemius will make its way down and extend or attach to the calcaneus via the calcaneal tendon here. So when the muscle contracts, this is going to extend the foot, which means we're going to plantar flex, plantar flex the foot. So please consider that when thinking about the gastrocnemius. Now, as we make our way back up.
Deep to the gastrocnemius, we have a synergist to the gastrocnemius, a muscle that will work together with that. This is going to be the soleus. So this is also going to plantar flex the foot.
Moving in from there, this large muscle here that gives rise to this large visible tendon, this is going to be the fibularis longus or the peroneus longus. So this is a muscle that's now going to function to evert the foot. So it takes the foot and kind of...
takes it out, reverts it. So that's fibularis longus. Moving up from there we see the extensor digitorum longus right here. This is a muscle that will give rise to several tendons now that extend towards the digits. When the muscle contracts this allows us to extend those digits.
And finally the last highly visible muscle we have here along the anterior aspect is the tibialis anterior. Notice Here is the tibia. So the tibialis anterior then is going to dorsiflex the foot. So this is going to be the antagonist to the gastrocnemius and the soleus. So these are the five muscles you will want to recognize here in the crural region.
Gastrocnemius, soleus, fibularis longus, extensor jitorium longus, and tibialis anterior. So we make our way now towards the posterior thigh. Here there are going to be three muscles that make up the hamstring group and the three muscles that are visible here are the biceps femoris, the semitendinosus and semimembranosus deep. So these guys would be the opposing muscles for the quadriceps group.
So if the quadriceps extended the thigh or the knee, I'm sorry, the biceps femoris are going to function to flex the knee. So, again, three muscles. Deep to that you do see the sciatic nerve there, but it's the biceps femoris, semitendinosus, and then semimembranosus that are visible there.