Anatomy - Lec.10

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Muscles of the Lower Limb (2)

Doaa' Rawwad

Rashed Jomard Sunday, 25/9/2011

Anatomy

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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...



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



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!



- 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,



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!



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 !



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.





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………..

http://www.getbodysmart.com/





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meaning). Walter Gropius

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Anatomy - Lec.10