Anatomy - Lec.9

8/3/2019 Anatomy - Lec.9

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Muscles of the Lower Limb (1)

Hala Shawareb

Rashed Jomard

Sunday, 25/9/2011

Anatomy

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Anatomy - Lecture 9Sunday, 25-9-2011Done by: Hala Shawareb

Muscles of the lower limbs..

We are here to achieve our goals Do you have any question about themuscles of the lower limbs? Because we are in a university we dontrepeat whats in the book. We analyze and discuss difficult areas. Okay?

Now, why do we do that? Because we have to answer this questionWhere is the Disease?

Most doctors count on ignorance of the patients and that is a bigproblem. Now what if you have an intelligent patient and he has aproblem and he asks you Where is my disease?

It is one of the most important duties to explain to patients Look yourproblem is in this part and Im going to do this and that but most peoplecount on ignorance of the patients. Patients are suffering, therefore theyare not in the mood for asking but you re supposed to tell them .

Lower Limb:

This lecture does not include everything you need to know, it onlyincludes difficult areas (general outline), so you have to refer to the book.Now, why do we have muscles in the lower limb? We have muscles thereso that we can move joints.


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I would like to group muscles according to function, so when I want tostudy muscles of the lower limb I have to study the joints first. We havethe hip joint, knee joint, ankle joint and then a group of small joints that

are close to each other that are the tarsal joints, sub tarsal joints,metacarpopharangeal joints (should be metatarsophalangeal joint) and interpharangeal joints (these are the joints that Im supposed to move inthe lower limb)

For example, one of the movements of the hip joint is Flexion (decreasingthe angle) and this is done by a group of muscles. There are extra pluses

on iliopsoas. So if we lose one of these muscles we can still do flexion of the hip but if we lose the iliopsoas muscle were going to lose a goodpart of flexion.

Then extension of the hip joint (back to normal anatomical position) andhyperextention. We use this movement a lot, we stand up we doextension, we climb stairs we do extension, we move and push our body

forward we do extension, so it is one of the most useful movement of thehip.

Abduction and adduction we dont use them as frequently as flexion andextension but still they are being done by two important muscles; gluteusmedius and minimus plus some other joint s so we dont really worry of losing a movement of a joint. Adduction is also being done by a group of muscle.

Rotation (lateral and medial) is also done by a group of muscles and thencircumduction (combination of all these movements) and I need musclesto move the hip joint in these groups.


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Knee joint , I need to do flexion which is also done by a group of musclesbut the hamstrings are the most important ones. Extension, flexion,locking and unlocking. You see , I cant do adduction and abduction at theknee joint because of the tight or type (not sure) of the joint.

Locking is a very important movement, when I move especially in walking,one of the stages of walking is straight up with one leg flying, so in orderto prevent the knee from bending flexion I have to lock the knee so thatthe thigh and the leg are fixed in position so it can bear the weight.


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Locking is done by medial rotation; when Im standing on one leg , thefoot is being fixed and the body is the moving part so I do medialrotation of the thigh on the tibia and I lock it .

Now when I take off the leg I have to unlock it, and this is done by amuscle called the poplliteus muscle . Some people cant lock their kneebecause of: 1. Weakness of the muscle

2. Problem in the nerves supplying these muscles

If you stand up at the gate of the university and start watching how the

people walk, you ll find different ways of walking, different problemsduring walking. When you go and read the book, you will not find manybooks like writing that one of the movements of the knee is medial andlateral rotation ; medial rotation of the femur on the tibia and lateralrotation back to the normal anatomical position, these are another namesfor locking and unlocking.

For the ankle , it is dorsiflexion or plantarflexion. These are importantmovements in walking because when one of the legs is on the groundand I want to lift the other one , I dont want the foot to drop ; because


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when it drops it shovels, I want to lift it (dorsiflexion). Because the anglebetween the foot and the leg becomes smaller, they call this flexion.Some people call it extension but it is dorsiflexion and the foot down is

plantarflexion or extension. I have very important muscles inplantarflexion because I force myself forward because of the extension.

How do I push myself forward? I extend the hip joint and I want to take itoff the ground so I plantarflex the foot and this is done by gastrocnemiusand soleus plus other muscles. Now Im not going to give you the ankle

joint or the joints of the foot but I would like just to mention that for the

ankle it is Plantarflexion and Dorsiflexion.

More peripheral joints, tarsal and subtarsal joints plus metatarsalpharangeal joint. Therefore, we are going to have different groups of muscles to do different movements.

Now what do you think gluteal muscles do? They are at the back of the

hip; so when they come down and insert on the femur what do they do?Extend it, plus medial rotation and lateral rotation, but usually lateralrotation.

Now theres another important movement during walking, (you are luckywe dont teach you walking because its complex ). When Im having oneleg on the ground, the other leg is flying, what happens to the pelvis? Itdrops. How do I stabilize it? A group of muscles on the landing siteshould contract to bring the pelvis straight these are abductors and theseare the gluteus medius and minimus .

How do I flex my hip? I must bring muscles anterior to the hip joint sothat they flex the hip joint. How do I Adduct ? I have to bring muscles


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from the medial side and insert them on the femur, so that when theycontract I have adduction.

Other people say: we are going to divide muscles not in relation to themovement of the joints but in groups . For example, muscles of the thighthat are around the femur, they are divided into anterior muscles, medialmuscles and back muscles. As well as muscles of the leg; they are dividedin the same manner.

What do usually anterior muscles of the leg do? If they come anteriorly

they do dorsiflexion, if they are swipping around the medial malleolous,they do plantarflexion. So you know now what the mechanics of thesegroups of muscles are.

What do you think posterior muscles of the leg do? They doplantarflexion. You see because of confusion, we are not going to useextension and flexion in the ankle, let us use dorsiflexion and

planterflexion.

What do you think lateral muscles do?Lateral muscles: if they go infront of the lateral malleolous, then they aredorsiflexors. If they go behind the lateral malleolous, then they areplantarflexors.

Muscles of the foot are going to have their own lecture.

Now we understand how muscles of lower limb are attached, we have avery important subject which is fascia of the lower limb.


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Whats the difference between muscles of the upper limb an d muscles of the lower limb?

MUSCLES OF THE UPPER LIMB do not have very thick prominent fascia;they do not have thickening of the fascia strapping the tendons in flexbecause they are not weight bearing. While in muscles of lower limb, wehave thick fascia (so we wear thick fascia in our lower limbs just likedivers suit). Thick fascia cannot expand; it holds the muscles to thebones and holds muscles together.

Fascia of the gluteal region is superficial and deep (No real clinicalapplication). But fascia of the thigh is very important; fascia of the thighis superficial and deep. The abdominal wall has 2 fascias; superficial anddeep, The superficial comes from the anterior abdominal wall andbecomes continuous with the lower limb (scarpas fascia). Now the deeperfascia of the abdominal wall which is the membranous fascia is not goingdown to the lower limb, its going to be inserted 1cm below the inguinal

ligament.

Now, the deep fascia of the thigh is called fascia lata, its very thick , itencloses the thigh as elastic stocking just like divers suit and therefore itprevents expansion. That is a big problem because inside this stockingwe have the femur and blood vessels, if the femur is fractured and wehave bleeding then this bleeding should produce swelling (like trauma atthe back in the anterior abdominal wall and in the upper limb; we haveswelling).

Now, can the thigh and the leg swell? The answer is no because of thefascia lata. Since it does not swell, its going to compress blood vessels,therefore blood will be cut off for the lower limb, for the distal part of


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fracture and tissues will die in few hour s therefore its very dangerous. Its life saving.

Once we receive people coming in an ambulance from a car accident andwe see different positions of the foot and the leg, we always immediatelygo to the thighs and look at them and feel them; because if we just lookat them we dont see great difference between the good thigh and theinjured one because expansion is going to be very little, so we feel themif one is soft and the other is hard that means there is bleeding and wehave immediately to make incisions to relieve the pressure, so the blood

can go to the peripheral part of the limb. T hats why we have to kn owthat the lower limb has thick fascia called fascia lata, especially laterally itis very thick and its called the Iliotibial tract .

Something which is read and not understood is the fascia here, so let meexplain little bit details:Now here is the anterior superior iliac spine comes down attaches to the

pubic tubercle, this is what? This is the inguinal ligament which has afiber that will attach to the iliac crest which is pectineal ligament. Now,the inside of the abdominal cavity has a fascia lining the anteriorabdominal wall which is fascia transversalis.

The doctor started drawing; Fascia transversalis will come this way here,at the mid inguinal point will come down as femoral sheath and it hassepta dividing it into compartments, this one is femoral canal, a herniamay come in this way, this is the femoral vein This is the femoral veinand the femoral artery is lateral and outside the sheath is the femoralnerve. So, theres an extension of the transve rsus fascia into the lowerlimb of the femoral sheath and the femoral sheath will stop and the bloodvessel will continue.


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Now fascia lata attaches to the iliac crest and comes down and attachesto the inguinal ligament and comes down this way. Here it has anopening its called the saphenous opening .

Look at the circle, this circle curves medially then up and then deeper tothe superficial fascia; this is called saphenous opening. Its a little bitconfusing when you read it in the book.

We dedicate ourselves to muscles, which muscle are you interested in?Gluteal region (here the doctor was using his slides to explain so in order

to understand what hes talking about, you can use GetBodySmart.com )

Now we look posteriorly, this is another way of studying muscles, whichmuscle is this? This is gluteus maximus coming from iliac crest. This issacrum, this is coccyx and then ligaments and fibers will do what? Willcome down posteriorly and laterally to be inserted in the Glutealtuberosity and upper part of linea aspera, this is the great extensor.

If we take off the gluteus maximus, we will see this muscle, coming frommore anterior part of the iliac crest curling around the gluteus surfaceand inserts on gluteal tuberosity and what? Partly undercover of gluteusmaximus. So if we take gluteus maximus reflected medially you will seemost of gluteus medius then If we lift gluteus medius we will see thismuscle; gluteus minimus.

Gluteus minimus totally covered by gluteus medius,; you cannot see theminimus unless you reflect. And gluteus medius is partly covered bygluteus maximus. Now, when you go to the lab and you see a musclehere, most students will say this is gluteus maximus. This is not, this isgluteus medius.


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This is an extensor (the maximus), midius and minimus are the greatabductors; the great stabilizers of the pelvis. In this area, gluteal muscles(Here the doc pointed at the three gluteal muscles)

Then we have this muscle here, a very good land mark, it comes from theant. surface of the sacrum and gets out of the pelvis; starts from the antsurface of the sacrum one on the right and one on the left comes out of the pelvis through the greater sciatic foramen and inserts on the greatertrochanter. This is called the piriformis (from Latin piriformis = "pear shaped"). The function of this piriformis is abduction, whether it is lateral

or medial rotator it depends on wh ether its inserted ant . or post. If it'sinserted Ant. = medial rotatorIf it's inserted Post. = lateral rotator

So thats a land mark we use it to identify the sciatic Nerve .

There is another muscle for identifying the sciatic nerve which originates

from the obturator membranem comes through sciatic notch and insertson greater trochanter this is called obturator internus.

We see a tondon here. This is the obturator internus, you see the sciaticnerve comes from below the piriformis muscle. This is the obturatorinternus and we have two muscles attached to obturator internus: sup.and inf. gemellus these are not very important.

When you inject intramuscular injection in the gluteal region, you have todivide this region into four quadrants. You always inject in the upperouter quadrant ; because if inject on the lower medial or at the point of transactional of these lines (the 2 lines that made the 4 quadrants) , you will
http://en.wikipedia.org/wiki/Pearhttp://en.wikipedia.org/wiki/Pearhttp://en.wikipedia.org/wiki/Pearhttp://en.wikipedia.org/wiki/Pear


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injure the sciatic nerve and we dont want that because the sciatic nerveinvolves the muscles of the post. part of the thigh and all muscles belowthe knee.

Look at this muscle above, what is the shape of this muscle? (Quadrates)

Its origin is ischial tuberosity and its insertion is quadrate tubercle nearthe greater trochanter and intertrochanteric crest of femur. This is thequadratus femoris . What does it do? It pulls the femur towards theacetabulum, so it is an adductor (also lateral rotator because itsposterior).This is how we study the muscles.

If you look at the gluteus muscles (mind map); there is the gluteusmaximus (the great extensor). What does it do? >>> Extends >>> lateralrotator >> because its posterior . Gluteus medius and minimus abductand medial rotation


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These are the quadratus femoris and the piriformis (reading from themind map). Obturator interus is not a very important muscle.

Tensor fascia lateral >> the thickest most lateral part of fascia lata is theiliotibial tract and it is attached to muscle. Anterior muscles of the thighhave two groups (Refer to getbodysmart.com).

The great extensors of the knee (four muscles) they come collect togetherand insert on one tendon called quadriceps tendon, four muscles eachhas its own origin but they collect in one tendon called the quadriceps

tendon. I nside this tendon theres the patella which is a sesamoid boneand then the tendon continues to be inserted into the tibial tuberosityand the n its called patellar tendon (above the patella its calledQuadriceps tendon b elow its called patella r tendon)

This is the great extensor of the knee plus other muscles, for example,the Sartorius. This is not an extensor; it is a flexor because it inserts post.

and it flexes the hip. It is called tailors muscle (because when tailors sitdown and put a piece of cloth they sit like this >> flexion of the knee andflexion of the hip and lateral rotation of the hip


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Now on the practical, you can put your hand behind the Sartorius and godown, you can feel the tendon of adductor magnus.

What is this muscle? It comes from the ant. surface of the femur, medialside, lateral side and intermascular septae, comes down and insert to thistendon here which is Quadriceps tendon which includes the patella andthen comes patellar tendon. This is one of the extensors of the knee.

What about this muscle here? It originates from this interrupted line(Linea aspera) medial septum and joins the quadriceps tendon but at the

same time it does not join here (the beginning of the tendon), it joins thetendon and THEN the medial side of the patella for a very good reasonwhich I will be telling you in moments.

a. Vastus Medialis b. Vastus lateralis


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This is the big muscle called vastus intermedias, here vastus medialis andhere vastus lateralis. They join the quadriceps tendon. Look at thedifference between vastus medialis and vastus lateralis, what do you find?

You will find that the lower fibers of the vastus lateralis join thequadriceps tendon. While the lowest fibers of the vastus medialis joinsthe quadriceps tendon and the patella. You know why? Because when youapply pressure on the patella, the patella will go lateral, the patella mustbe in the midline to do its mechanical action in function of the knee, soto correct this lateral movement, you need to pull the patella medially. So

what do you do? You extend the fibers of the vastus medialis lower down.

Now there are people who are going (for some reasons) to have weakvastus medialis will come and say look when I walk my patella clickslateral that is because they have a problem in the vastus medialis or itsnerve supply.

The last muscle is this one, which is quiet different because its bipennate .Its called rectus femoris . It takes origin from two points one point isabove the acetabulum therefore physiologically it has a weak action onthe hip and a very good action on the knee because of the distance. Whenyou collect the up-mentioned 4 muscles together, they'll make thequadriceps muscle.


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Doctors are men who prescribe medicines of which they knowlittle, to cure diseases of which they know less, in human beingsof whom they know nothing Voltaire

Done By: Hala Shawareb

Very special thanks to Dr. Islam Haddad for helping me

This is the Origin and insertion of therectus femoris

Anatomy - Lec.9

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