the

Muscles of the Thigh Part 1 - Anterior Compartment - Anatomy Tutorial

okay so I'm going to do a couple of

tutorials on the muscles of the thigh so

the muscles of the thigh are arranged

into three compartments you've got an

anterior compartment medial and

posterior compartment and these are

separated by inter muscular scepter so

the anterior compartment is known as the

extensor compartment the medial

compartment now is the adductor

compartment and you've got the posterior

compartment which is the extensor

compartment so these various different

compartments have different actions on

the hip and knee joints and the

different compartments are supplied by

different nerves so the anterior

compartment here is supplied by the

femoral nerve the medial compartment is

supplied mainly by the obturator nerve

and the posterior compartment of the

thigh is supplied by the sciatic nerve

so in this first part of the tutorial

I'm going to talk about the anterior

compartment of the thigh so this is this

group of muscles here anteriorly in the

thigh obviously and these muscles are

supplied by the femoral nerve and you've

got five muscles in this compartment

you've got the four large quadriceps

femoris muscles and then you've also got

the Sartorius muscle as well as these

muscles you've also got the terminal

ends of two muscles here so the iliacus

and so ice major so you can see them

superiorly here in the anterior

compartment the terminal ends of these

two muscles so I'll show you these

muscles now so we'll just take a look at

the iliopsoas muscles so the iliopsoas

muscles are the psoas major and the

iliacus so collectively the iliacus and

source are known as the iliopsoas

muscles so the iliacus muscle is this

muscle here and it inserts onto the

lesser trochanter of the femur together

with the and so last major muscle so

this is the source major muscle here and

they have this common insertion point on

the

sir to counter of the femur so the

iliopsoas and the iliacus muscle are

collectively referred to as the

iliopsoas muscles so you can see here

I've just highlighted the iliacus in

size major muscles so you can see the

origin and insertion a bit more clearly

so here you can see the size major

muscle originating on the sides of the

vertebral bodies and the transverse

processes and the intervertebral discs

and it originates from the vertebral

bodies from L sorry t12 down to l5 and

then you can see it's insertion on the

lesser trochanter of the femur and also

the iliacus muscle which sits in the

iliac fossa and then it inserting in the

same place on the lesser trochanter so

what these muscles do is that they flex

the hip flex the thigh at the hip joint

okay so the next group of muscles in the

anterior compartment are the quadriceps

femoris muscles so you've got four

muscles in this group you've got the

rectus femoris muscle and you've got the

three fastest muscles so you've got the

vastus medialis

lateralis and intermedius which lies

under the rectus femoris muscle so the

rectus femoris muscle is interesting so

it originates on the pelvis so it has

action both at the hip joint and at the

knee joint those the fastest muscles

only act at the knee joint

so the rectus femoris muscle is this

muscle here which lies in the anterior

compartment and it's the most

superficial muscle so this muscle and

originates on the pelvis on the anterior

superior iliac so I anterior inferior

iliac spine and it's also got another

head which is called the reflected head

which isn't shown on this model but it's

reflected back and it originates just

superior to the acetabular fossa so

there's two heads to the rectus femoris

muscle one originates on the anterior in

the iliac spine and the other is

reflected back and originates on the

just superior to the acetabulum and

that's called the reflected head the the

head that originates on the anterior

inferior iliac spine is known as the

straight head so the rectus femoris

along with the vastest muscles and it

inserts via the quadriceps tendon onto

the patella bone and the patella then

inserts onto the tibia by the patellar

ligament so muscle is attached to bone

by tendons and bone is attached to blade

by ligaments so the quadriceps for most

tenderness is common insertion onto the

patella bone and the patella then

inserts onto the tibia via the patellar

ligament or rather is attached to the

tibia via the patellar ligament so

because the rectus femoris originates on

the pelvis it can it flexes the thigh at

the hip

whereas the vastus muscles don't do that

because they originate on the femur so

we'll just take a look at the vastus

muscles so I'll just get rid of the

rectus femoris muscle and you can see

this muscle here sitting laterally so

this is the vastus lateralis

and again this it originates on the

femur and it inserts onto the patella

Vavi quadriceps femoris tendon then

medially you've got this teardrop shaped

muscle which is known as the vastus

medialis because it's it's medially and

this again inserts by the quadriceps

femoris tendon on the patella and just

under the rectus femoris muscle which I

removed you've got this muscle here the

vastus intermediate so these three

muscles will originate on the femur and

insert onto the patella via the

quadriceps femoris tendon and they

extend the leg at the knee joint

so the final muscle we have is this

muscle here called the Sartorius this is

a strap black muscle which runs from the

anterior superior iliac spine all the

way down to the medial surface on the

proximal tibia so this is this is the

Sartorius muscle I acts to flex the

thigh at the hip joint and also flex the

thigh at the knee joint so just take a

look at it more isolated so you can see

we've got the anterior superior iliac

spine here where the Sartorius muscle

originates and just blade got the

anterior inferior iliac spine where the

rectus femoris muscle originates and

this Sartorius winds around obliquely

descending along the thigh to insert on

the medial surface of the proximal tibia

so the insertion point here is just

anterior to the insertion point of the

gracilis and the semitendinosus muscle

so you can see you've got this the

hamstring muscle here and you've got the

gracilis so they insert just behind the

insertion point of the Sartorius muscle

so that's the Sartorius so those are the

muscles of the anterior compartment of

the thigh you've got the iliopsoas

muscles you've got the quadriceps for

most muscles and you've got the

Sartorius muscle and the muscles that

originate on the pelvic bones have

actions at the hip and knee and the

muscles that originate only on the femur

only act on the knee joint

so that rectus femoris muscle and the

iliopsoas muscles act on the hip and the

quadriceps femoris muscles act at the

knee and these muscles are innervated by

the femoral nerve