In this video we will be covering some
of the muscles of the thigh and the hip.
We will begin by reviewing the muscle attachments and their actions which will be visually represented
using our skeleton.
And then we'll move through a yoga flow that draws attention to these muscle groups.
I promise that this is the most material heavy
video so stick with me as we make our way through.
Let's start with the muscles of the hamstrings.
The hamstrings are comprised of 3 muscles.
The biceps femoris, semimembranosus, and semitendinosus.
All of these muscles proximately attach at the ischial tuberosity.
In the case of the biceps femoris, the long
head proximally attaches at the ischial tuberosity, while the short head proximally attaches along
the linea aspera on the upper two thirds of the proximal femur.
Both the long and short head of the biceps femoris distally attach at the head of the
fibula.
Right here.
As you can see, shortening of the biceps femoris leads to extension of the thigh at the hip.
Additionally, shortening or contraction of the biceps femoris draws the head of the fibula
relatively closer to the muscles proximal attachment at the ischial tuberosity.
which also causes flexion of the leg at the knee.
Because the biceps femoris crosses over 2
joints: the hip and the knee, it's able to enact 2 different movements over one at each
of these joints.
The semimembranosus and semitendinosus are very similar to the biceps femoris in the journey
they take to their attachments.
Both of these also proximally attach at the ischial tuberosity and only differ in their
distal attachments.
The semimembranosus proximally attaches at
the ischial tuberosity and makes its way across to distally attach at the posteromedial surface
of the proximal tibia.
Right here.
The semitendinosus also proximally attaches at the ischial tuberosity and makes its way
down to distally attach at the upper inner surface of the proximal tibia.
Both of these muscles when contracted cause
extension of the thigh at the hip.
Also as both of these muscles contract they are able to draw their distal attachment closer
to the proximal attachment at the ischial tuberosity which causes flexion of the leg
at the knee.
Again, just like the biceps femoris both of these muscles cross over both the hip and
the knee.
Which means that they're able to cause movement
at both of these joints.
Moving to the front of the thigh we have the quadriceps muscles. As the name suggests, the
quadriceps is comprised of 4 different muscles.
The rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius.
All of these muscles proximately attach along the ililum and the shaft of the femur.
They distally attach onto the tibial tuberosity
via the patellar tendon.
Just like the hamstrings, the quadriceps muscles cross over two joints, the hip and the knee.
And therefore are responsible for movement at both of these joints.
At the knee as the muscle shortens the tibial tuberosity is drawn anteriorly which causes
extension of the leg at the knee.
Looking more proximately, contraction of the
muscle also causes flexion of the thigh at the hip.
Now continuing down to the lower leg we will start talking about the gastrocnemius.
This powerful muscle proximally attaches at the distal femur.
And distally attaches at the calcaneus via the calcaneal tendon.
Just like the quads and the hamstrings, the gastrocs crosses over two joints, the knee
and the ankle.
So it causes movement at both of these joints.
At the level of the knee shortening of the muscle causes flexion of the leg at the knee.
At the level of the ankle, shortening of the muscle draws the calcaneus superiorly causing
the toes to point down, or plantarflexion of the foot at the ankle.
The soleus is a deeper calf muscle.
It proximally attaches at the tibia and the fibula and it also distally attaches onto
the calcaneus via the calcaneal tendon.
As the muscle shortens it is responsible for plantarflexion and you can see this happening
as the toes point downward.
The next set of muscles that we will cover before moving into yoga poses that cover the
lower extremity are the hip flexor and hip extensor muscles.
The 2 major hip flexor muscles that we will
discuss are the iliacus and the psoas major.
Together these muscles are known as the iliopsoas.
The iliacus muscle proximally attaches at the upper 2 thirds of the inner surface of
the illium.
Up to the inner lip of the iliac crest to the anterior sacroiliac joint.
It hooks over the anterior aspect of the pubic
bone to distally attach at the lesser trochanter of the femur.
The psoas major proximally attaches along the transverse processes discs and bodies
of lumbar vertebrae one through five.
As well as the body of the twelfth thoracic vertebrae.
So that is right here, all along here..
just like the illiacus, the psoas major hooks
over the anterior aspect of the pubic bone to distally attach on the lesser trochanter
of the femur.
The illiopsoas is responsible for flexion of the thigh at the hip.
As you can see by taking this journey over the pubic bone as these muscles shorten they
are able to lift the lesser trochanter up and therefore the whole femur is lifted causing
flexion of the thigh at the hip.
The gluteus maximus is the major hip extensor
that we will discuss today.
The gluteus maximus proximally attaches at the posterior surface of the ilium and distally
attaches at the gluteal tuberosity of the proximal femur.
It also distally attaches along the iliotibial band although the IT band is not visualized
on a skeleton model.
As the gluteus maximus shortens or contracts
it draws the femur posteriorly with relation to the pelvis which causes extension of the
thigh at the hip.