- Hello massage nerds.
Today we're gonna be doing part two of lesson eight,
which are the muscles for knee movement,
Okay, for extension and flection of the knee.
I'm gonna start by talking about the quads.
Remember that quads means 4 muscles,
which are the rectus femoris originates right here,
at the anterior inferior iliac spine, the ASIS,
it originates right there.
It's the only one of the quads that crosses two joints,
because it also helps you to flex the hip,
so it works on both joints.
So it originates at the ASIS,
and then it goes all the way down,
crosses through the patella, ligament and tendon,
and then inserts at the tibial tuberosity.
Then you have your vastus lateralis,
which originates right here on the femur,
It doesn't originate by the hip,
on the linea aspera of the femur.
Okay, and then it goes down,
again, it crosses the patella through the patella tendon,
into the tibial tuberosity.
In between you have the vastus intermedius
will be the green one right here,
and it's underneath the rectus femoris, okay?
So then you're gonna go...
It goes right here underneath,
and I drew it in green, so you could see it.
And again, it inserts into the tibial tuberosity,
and then you have your vastus medialis,
obviously, 'cause it's more on the medial side.
So this one would be the proper one,
it's the one that looks like a tear drop right here,
and it originates on the linear aspect of the femur,
on the medial side, Okay.
Down here, you have your pes anserinus,
or pes anserinus,
which is where three muscles insert.
So one of them is the Sartorius.
The Sartorius is the longest muscle in your body.
It originates at the highest point,
at your anterior superior iliac spine.
So at the ASIS and it crosses over,
and it goes down and insert right here
at the pes anserinus,
this is also called a tailor's muscle,
because it's the one when tailor's used to sew,
they used to cross their legs.
So if somebody comes in,
with an injury where it's hurting,
because they've been crossing their leg,
you make sure you check out their Sartorius muscle.
So this is the another muscle here,
and you have three insertions,
right here at the pes anserinus,
which will be the sartorius,
the semitendinosus and the gracilis.
And the gracilis is one of the adductors,
you saw that in the part one of lesson eight.
catarrhalis, rectus femoris, vastus intermedius,
because it's in between inter means in between,
and the vastus medialis which is on the medial side.
They all connect through the patella tendon,
and become the ligament here also,
for the for the joint that it crosses of the knee,
and they all insert at the tibial tuberosity.
So those are the quads.
Now we're gonna move on to the hamstrings.
Okay, so for the hamstrings, we have three,
we have the biceps femoris, the semitendinosus,
and the semimembranosus.
They all originate at the ischial tuberosity.
The ischial tuberosity or the ischium, is your sits bone,
also known as your sitz bone.
So the bone where you sit on,
remember the gluteus Maximus moves out of the way,
for you to sit down,
and so the ischium is exposed,
and then you can see the origins of the
biceps femoris, the semitendinosus,
and the semimembranosus.
These muscles sometimes,
when your hamstrings are really tight,
a lot of times the biceps and just the hamstrings will pull.
So they pull down here,
and they make cause pain in the low back.
So make sure you always check the hamstrings too,
when somebody is having low back.
you've got your tuberous ligament,
especially the biceps femoris,
connects also to the tuberous ligament,
and it can get really really tight.
So the biceps femoris originates at the ischial tuberosity,
and then this is the long head and it crosses,
and then inserts at the head of the fibula.
And the short head originates right here
at the linear aspirin of the femur,
and it also inserts right here on the fibula side.
Remember the fibula bone is the one on the lateral side,
and it doesn't really bear any weight.
It only bears like 10% of your body weight,
it's the tibia that does all the work of holding you up.
Then you have your semitendinosus,
which originates in the medial part of the ischium,
and it goes down and it inserts at the pes anserinus,
on the medial side by the knee.
So whenever you have somebody that has knee pain,
make sure you check the pes anserinus,
'cause remember there's three muscles
that are attached there,
so, always check that out.
Now, the semimembranosus is the most medial,
of the hamstrings,
and it originates obviously on the medial side,
of the ischium, and it goes down and it crosses over,
and it also inserts right here,
on the head of the tibia.
So, Oh, the popliteal.
So the popliteal, is this muscle right here,
and it's called, the key that unlocks the knee,
in order to do flection.
So when this releases, then you can flex,
remember the hamstrings are the ones that are for flexing.
So flex your knee, flex your leg, okay.
So this is flection, these muscles are tightening up,
they're pooling the knee.
Okay, so they're closing the angle,
the popliteal and the three hamstrings,
are pulling and closing the angle, and that's flection.
And then extension would be,
the quads pulling the leg back,
and still the quads,
are the ones that become the agonist at that point.
When you extend the knee,
the quads become the agonist,
and this become the antagonist.
And when you are flexing,
so when you flex this become the agonist,
and this become the antagonist.
'Cause it's a give and take,
remember muscles work in groups, they work together.
So, here you have your quads, your hamstrings,
the popliteal, and the Sartorius,
which is the longest muscle, would be the Sartorious.
And that is the part two of lesson eight,
for the movement of flexion and extension of the knee.
Thank you, Elizebeth for being my model,
she's got great legs.
(all laughing)
Well tackle the next one.
That's going to be your homework guys,
to make sure and draw all the muscles,
and pay attention to where they originate.
And remember that the rectus femoris,
is the only one that crosses both joints,
the hip and the knee,
because it works on both joints.
So I hope this helps you, and make sure that you subscribe,
and thank you for your support.
I truly appreciate it,
all of you that support me, leave me comments,
and until the next time, create a great day.