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Subject:
Done by:
Doctor:
Date:
Muscles of the Lower Limb (2)
Doaa' Rawwad
Rashed Jomard Sunday, 25/9/2011
Anatomy
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Sub-system:
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Anatomy Lecture 10/ MSS
2011-9-25 / Sunday
Muscles of the thigh Please refer to the book and to the mind maps while reading this lecture.
The anterior group of muscles (continued):
The Dr continued what he had started in the previous lecture: Also in the anterior part of the thigh we have another landmark, this landmark is what
we call the femoral triangle. Here are the edges of this triangle:
- The inguinal ligament
- The lateral border of adductor longus
- The medial border of Sartorius
The Dr is drawing on the projector:
This is the place where you see the femoral canal and we have inside the femoral
sheath, we have the femoral vein and the femoral artery, and then outside the sheath
we have the femoral nerve. If we want to look for this muscle which is the Iliopsoas
or this muscle which is the pectineus you can't see them because they are covered with
the neurovascular bundle...
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The psoas minor muscle is not constant; you see it in some people and you don't see it
in others… but you see the psoas major is arising from 15 points; 5 slips and each slip
has 3 poinsts of attachment. then this muscle - psoas major- comes down and meets
the iliacus muscle which arises from the iliac fossa, and these two muscles join to
form one tendon (the same arrangement as that of the quadriceps tendon), and then it
will be the iliopsoas muscle, and it is inserted into the lesser trochanter, and it is one
of the great flexors of the hip.
Now we have an idea about the anterior group of muscles... and here is a quick idea
about medial group of muscles.
The medial group of muscles:
The medial group of thigh muscles are named as adductors of the thigh at the hip
joint.
1. Pectineus muscle: It originates from superior ramus of pubis, going down and
lateral, and then it is attached to the upper part of linea aspera. The pectenius is
a "funny!!" muscle some people say it is two muscles because it has a double
nerve supply; the femoral nerve and the obturator nerve.
2. Adductor longus: It is just inferior to the pectineus.
3. Adductor brevis: It is posterior to the
adductor longus.
4. Adductor magnus: If we remove the two
muscles above we will see this muscle (deep to
adductor longus and brevis), which is the
biggest adductor . It inserts into linea aspera,
and it has holes in it. Anterior to these holes
we have the profunda femoris artery, and
through these holes it sends branches into the
posterior group of muscles.
5. gracilis: it is the most medial one
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These are the medial group of muscles and they have their own nerve supply which is
the obturator nerve, this muscle here -which is the adductor magnus- it has a double
nerve supply; the obturator and the sciatic from posterior.
The posterior group of thigh muscles (flexors):
They are called the hamstrings, and they include 3 muscles:
1. biceps femoris :
This muscle has two heads;
The long head originates from the ischial tuberosity.
The short head comes from the posterior part of the femur; linea aspera.
We call it biceps femoris to differentiate it from biceps brachialis.
Then the two heads come down and insert into the lateral part of the leg; the head of
fibula …. One year we had this question:
- The action of which muscle becomes very painful if we have fracture of the
upper end of fibula?
You see … muscles have attachments; origin and insertion. If you fracture the origin,
then the action of this muscle becomes painful! Not weak, but painful. For example,
the deltoid muscle is attaches to the clavicle acromion process and spine of the
scapula. So if the clavicle is fractured, you should know that any movement of the
shoulder will be very painful, so you shouldn’t ask the patient to do abduction, it's
painful!! He can't do such movements not because the muscle is paralyzed, but
because the movement is painful.
What happens if the ischial tuberosity is fractured? Then most of the muscles of the
thigh will not function because the functioning is painful.
So if you’re kidding with your friend, and you tell him to sit down on a chair, then you
cheat him and you remove the chair O.o and he falls down on his ischeial tuberosity!
So if it breaks, he will not be able to flex his thigh because of the pain!
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- A question by one of the students: what if the fracture was in the insertion?
It will be the same; painful movements.
- Another question: how can we tell if the fracture is in the origin or in theinsertion of the muscle?
By doing an x – ray picture.
2. Semimembranosus: when you hold it and you go up, you’ll see that the tendon
of its origin is a membrane; it is a very thin flat aponeurosis, therefore it is
called semimembranosus.
3. Semitendinosus: and is so called because when you go to the lab and see the
cadaver, you’ll see that half of it is a tendon and half of it is a muscle; therefore
it is called semitendinosis.
Muscles of the leg:
In the leg we have the same problem of the fascia, as we have fascia lata of the thigh
(the deep fascia of the thigh), we have in the leg what we call the crural fascia (the
deep fascia of the leg) and it is a continuation of the fascia.
When there is a fractured bone, then there is an injured blood vessel or there is
bleeding. So here you don’t see the swelling of the leg, here you see a tense leg!
because the fascia will prevent expansion of the leg. So if the leg can't expand to the
outside, then it's going to press anything inside the fascia; like the veins and the blood
vessels, and you will stop having a peripheral pulse! And you have to immediately puta longitudinal incision to relieve the pressure.
Posterior muscles of the leg:
Now we will talk about the posterior muscles of the leg.We need these muscles during
walking, when I walk I land, I unlock the knee then I prepare myself to push myself
forward. Once I push myself forward, and I will contract the gluteus maximus. Then
when I contract the gluteus maximus, I feel my heel is elevated and I want to continue,
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so I need to do planter flexion of the foot so that I will fly; therefore I need a great
power. Bur how do I get it? I get it from these muscles:
1. Gastrocnemius:
This muscle has two heads crossing the knee and coming from above the condyles of
the femur, therefore it has a weak action on the knee joint. Then they join together and
form a strong tendon that is inserted into calcaneus bone.
2. Soleus:
This muscle is deep to gastrocnemius muscle, arising from fibula, interosseous
membrane, and tibia… And then coming down and joining the tendon of the
gastrocnemius. Then soleus muscle inserts on the upper part of the calcaneus.
Now iliopsoas are two muscles that have one tendon, quadriceps muscles are four
muscles that form one tendon, and here is another example two muscles that form one
tendon.
These two muscles -I mean soleus and gastrocnemius - they act together for
propulsion; forceful planter flexion.
Soleus muscle is full of blood vessels and it is called “the second heart”. When I
contract my soleus, the blood will be pushed upward. When soleus muscle gets
stabbed, it will bleed a lot because it is full of veins.
Now in the army < fel jaish> the soldiers are supposed to stand for several hours
where they are not allowed to do any movement !! even if a fly settles down on
your nose :P and that is just to teach them patience they are allowed to do just
one movement which is planter flexion to avoid fainting! So once they feel thatthey are going to faint, they elevate themselves one or two times and stand on
their toes, then they come back to their standing position. When they do that they
contract their soleus and gastocnemius muscles, and then they feel fresh again
Achilles tendon is the tendon of soleus and gastrocnemius muscles. Achilles is a
Greek leader that received an arrow that cut his Achilles tendon, and was not able
to walk! So it was named after him. This tendon you can feel it, it's very tough!!In real life you can't cut this tendon even with scissors, the scissors will break!
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Now, we need more propulsion, so what do we do? We have more muscles to propel
forward. As I said we need gluteus maximus to contract first, then we need planter
flexors such as gastrocnemius and soleus, and then the last part that leaves the ground
during walking is the big toe; the hallux, therefore we need a strong and a powerful
planter flexor of the big toe which is the flexor hallucis longus.
3. flexor hallucis longus:
This muscle is oblique to have a little bit extra length. Also this muscle is bipennate;
this means that the muscle has central tendon, and the muscle fibers are on both sides
of the tendon.
And the flesh part is as low as it turns around the medial malleolus of tibia. So this is a
very powerful muscle where the flesh or the contractile part on both sides of the
central tendon go as down as the medial malleolus. Therefore this is an indication that
this is a very powerful muscle because it is oblique, bipennate, and the flesh part is as
low.
I can't flex the big toe only; I need to flex the other toes as well!
If you cut the hallux you can walk but not that efficient! Because the toes can't replace
the big toe…
Now there is a big problem with the big toe if the nail of the big toe grows to the deep,
so it becomes painful when pressing on it, therefore you will see that the person is not
walking properly … So if the right side is painful, you will walk properly on the left
side, but on the affected side -which is the right- you extend the big toe so you walk in
a way that you can't press on the big toe because that is painful.
You’re lucky that we don’t give you the walking process as a process! But start to
look how people walk, and if you are a very good observer, you can identify where the
disease is if someone's way of walking is not that good…
There are people who have a weak gluteus medius and minimus so they walk this way
((the Dr. start walking in a funny manner )) they cannot stabilize their hips !
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Anterior muscles of the leg:
They can be of two types: - If they go anterior and stay anterior, then they are dorsiflexors. - If they go anterior and hook around, then they are planter flexers .
1. Tibialis anterior : This muscle is a good example on a muscle being anterior and a dorsiflexor of the foot
at the ankle joint. It's just lateral to tibia, and then it comes down then it becomes a
tendon in front of tarsal bones. Because it is in front of tarsal bones, then it's a
dorsiflexor muscle, and it also inverts foot at the intertarsal joints.
2. Extensor digitorum longus:
It's deeper and lateral to tibialis anterior. As it comes down, it splits into four tendons.
Note: it is always better to stick to dorsiflexion and plantar flexion, but some people
call the dorsiflexion as extension.
3. Extensor hallucis longus:
This muscle is between the tibialis anterior and the extensor digitorum longus. It
emerges a tendon. We don’t see this muscle because it’s deep to the two above
muscles, it extends the hallux.
Lateral muscles of the leg:
Lateral group of muscles are called peroneus. We have two muscles:
Peroneus longus
Peroneus brevis
The third peroneus muscle which is peroneus tertius belongs to the anterior group of
muscles.
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The Dr said that our knowledge about muscles doesn't end here! We have
to study them from the book because the lecture gives headlines only…
At the end of the lecture the Dr. showed us how to use
www.getbodysmart.com to study muscles…
THE END
It was a pleasure for me to write this easy lec hope you like it & get
benefit …
sorry for any mistake and sorry if it was done lately but be sure that it was
out of my hands !!!
2keed ma ra7 2nsa 27keelek shokran ,, my sis and my best frn 3hed <3
<3 thanks for everything 3hed mn elboshar lal 6eba3a :PPPP may 2lla
bless u hny <3
And special thanks for u nadia hawash 3la el flash memory :PP ya 27la
jarah
See u in the next system………..
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(Only work which is the product ofinner compulsion can have spiritual
meaning). Walter Gropius
NOOR SAMA