LOWER LIMB

As we know the bony part of the body is divided into Axial and Appendicular (upper and lower Limbs)

Bones of the Lower limb:

1-Pelvic Girdle: composed of:

1. Right hip bone : is formed by 3 bones connected with each other at a cup-shaped cavity called

acetabulum, the union site of these bones used to be cartilage, then they Ossify at age of 18

years.

A- Ilium ( Superior )

B- Ischium (Post.): you sit on it,

C- Pubis (Ant.)

2. left hip bone

3. Sacrum (Post.)

4. Coccyx -tail bone-(Post.)

These bones are united by 4 joints:

A. Sacroiliac Joint : between Sacrum and Ilium , left and right

B. Sacrococcygeus joint : between Sacrum and Coccyx

C. Symphysis Pubis : between the right and left hip bone

2-Femur: it is a long bone (the longest bone in the body), it is convex ant. Concave post. Which gives the

bone strength. It has; if it was vertical it might cause crash when jumping.

A- Proximal End:

a. Head

b. Neck

C. Greater Trochanter (lateral)

d. Lesser Trochanter (medial)

e. Intertrochanteric line (between Greater and Lesser Trochanters anterior)

B- Distal End:

a. Medial Condyle and Epicondyle

b. Lateral Condyle and Epicondyle

c. Patellar Surface of Femur, which is designed for Patella to slide over, and it is covered by

Hyaline Cartilage. (Anterior view)

d. Intercondylar Fossa, which is between the 2 condyles, and for the 2 Cruciate ligaments

(posterior view)

e. Medial and Lateral Supracondylar line

C- Shaft:

Anteriorly: it is convex and smooth.

Posteriorly: it is concave and rough, it is rough because it has linea Aspra, which is a

rough line for Muscles attachment.

D- Head covered with Hyaline Cartilage

E- Neck

The Axis of the Neck and the Axis of the Femur forms an Angle, in Males it is 1250 but in

Females it is smaller than this.

3-Tibia: It contains Tibial Tuberosity, which is very important for Muscles attachment.

4-Fibula

Layers of the Thigh:

1- Skin

2- Superficial Fascia: contains 2 veins: Great and Small saphenous veins, which is common to have

varicose vein, especially in women. These 2 veins carry blood AGAINST gravity, unlike the Cephalic

and Basilic Veins.

A common Disorder in these 2 Veins is stagnation of blood, which causes a change the

cylindrical shape of the vein to swollen vein (dilated vein). So, the wall of the Vein will be

thinner, which may cause leaking of blood below skin.

3- Deep Fascia (Fascia Lata): it is thick and composed of dense connective tissue, mainly composed of

Collagen fiber type 1, which is stronger than steel in compliance and stretching. The Deep Fascia

sends 3 symptoms that divide the thigh into 3 Compartments.

The Septums are:

a. Lateral

b. Posterior

c. Medial

They divide the thigh into 3 compartments

The Compartments are:

a- Anterior ( Extensor Comp.): its muscles are extensors for the knee joint

and supply by femoral nerve.

b- Posterior (Flexor Comp.): its muscles are flexor for the knee joint.

c- Medial (Adductor Comp.): its muscles are adductors for the hip joint and

supply by obturator nerve.

The Deep Fascia is thickened lateral to form a ligament extending from the Ilium to the Tibia,

called the ilitibial Tract, which confirm the extension of the knee (lock the knee). Therefore,

Gymnastic Athletes when they land on the ground with an extended knee, it may cause

injure ligaments of the knee.

Each compartment has it is own muscles, nerve supply, arterial supply and common action.

In fetus the lower limb rotated 90 Degrees medially just like the heart, that’s why the

anterior compartment contains extensor muscles, unlike the upper limb. In addition, some

new born may suffer from congenital dislocation of hip (congenital hip dysplasia), because

the lower limb did not rotate perfectly.

Nerves of the Lower Limb

i. Lumber Plexus: originated from ventral rami of L1-L5

1. Femoral Nerve: originated from L2-L4 posterior divisions of Lumber Plexus,

supplies the extensor muscles of the thigh.

2. Obturator Nerve: originated from L2-L4 anterior divisions of Lumber Plexus,

supplies the adductor muscles of the thigh.

3. Sciatic Nerve: originated from ventral rami of L4, L5, S1, S2, S3, so it is

originated from sacral and lumber plexus (post. Comp of thigh and leg)

4. Superior Gluteal Nerve: supplies Gluteus Minimus and Medias and Tensor

Fascia Lata.

5. Inferior Gluteal Nerve : supplies ONLY Gluteus Maximus

Anterior Compartment:

All supplied by Femoral Nerve, Except Psoas muscle.

Sartorius: which means tailor in Latin, this muscle originates from lateral and inserts

in medial side of the thigh.

Action: flex the Hip and the Knee

Rectus Femoris: prime extensor.

Action: flexion of the Hip, Extension of the Knee

Vastus Lateralis

Vastus Medialis

Vastus Intermedius

Action of the Vastus Muscles: Extension of the Knee

The Vastus muscles and Rectus Femoris are called Quadriceps Femoris.

Runners may be subjected of paralysis of the Quadriceps Femoris Muscles.

Psoas (with silent P):

Nerve Supply: Lumber Plexus

Action: Prime Flexor of the Hip joint

Iliacus

Nerve supply: Femoral Nerve

Action Prime Flexor of the Hip joint

Note that: both the Psoas and iliacus are inserted on the lesser trochanter; so any fracture in it will cause

losing the ability of flexing the thigh at the hip joint.

Rule: if a muscle crosses two joints; it performs two opposite actions except for Sartorius; because it

changes its axis.

In case if you have any note especially on the medial compartment & the leg; please contact Omar Sami

on FB as he added them to the summary.

Medial Compartment:

All supplied by Obturator Nerve and all are Adductors.

Adductor Longus Adductor Brevis Adductor Magnus

Action of the Adductor muscles is adduction of the Hip joint

Gracillis:

Action: Adducts the Hip join, and flexes the Knee joint.

Paralysis of this muscle occurs in Horse racers, which is called Charlie's horse.

Pectineus: Action : Adduction of the Hip joint

*Adductor Magnus: This muscle is located between the medial and Post. Compartment, it has

2 parts:

a. Adductor part:

Action: Adduction of Hip Joint.

Nerve: Obturator Nerve.

b. Hamstring part:

Action: extension of Hip.

Nerve: Sciatic Nerve.

Adductor Tubercle (Opening): A defect between the insertion of the Adductor and

Hamstring part of the Adductor Magnus, and it contains popliteal Artery and Vein.

Adductor Magnus is pierced by 4 branches from the Deep Femoral Artery (Profunda

Femoris, which is the largest branch of the femoral Artery), these branches perforate

Adductor Magnus and supply it, to reach the Post. Compartment. (“as.” In the slides

Means Arteries)

Arterial supply of the medial compartment:

1- Obturator artery.

2- Deep femoral artery; which is the largest branch of the femoral artery, also called profundus

femorus artery.

Both Gracilis and Pectineus muscles adducts the thigh at the hip joint; while gracillis also flexes the

leg at the knee joint.

Adductor opening:

Passes through it the femoral artery to be called popliteal artery.

Passes above it the femoral vein to be called the popliteal vein.

We have five extensors for the hip joint and they are:

1- Semitendinosus.

2- Semimembranosus.

3- Biceps femorus.

4- Hamstring part of the adductor magnus.

5- Gluteus maximus.

Remember that:

Obturator internous belongs to the gluteal region while the obturator externous

belongs to the medial compartment. And both of them causes lateral rotation of the

thigh at the hip joint.

Gluteal region

Gluteal Region is formed by the hip bones, which is composed of Ilium, Ischium, and Pubis.

The external aspect of the ilium shows 3 lines:

a- Anterior Gluteal Line

b- Medial Gluteal Line

c- Posterior Gluteal Line

These lines give Origins for the Gluteal Muscles

Bones of the Gluteal Region:

1- Ilium: it looks like the Oriental Fan, it has:

i. body,

ii. Iliac Crest: upper free border

iii. Ant. Sup. Iliac spine: Ant. End

iv. Post. Sup. Iliac Spine: Post End

2- Ischium: It

has :

i. Ischial

Tuberosity: the part we sit on

ii. Ischial

Spine: separating greater and lesser Sciatic notch

*Sciatic Nerve (Largest Nerve in the body) passes in the

Greater Sciatic foramen.

* These Notches are “Inverted” by the Sacrotuberus

ligament, which change these notches into 2 Foramens:

A. Greater Sciatic Foramen: the gateway of the Pelvis

B. Lesser Sciatic Foramen: the gateway of the Perineum

(private area)

* notice that the gluteal region is divided into four quarters

by two lines & The safest area to give an Intramuscular

Injection is in the upper lateral quarter of the gluteal Region

(Rule of thumb is applied here, refer to the picture); because

it has the minimal amount of nerves and blood vessels.

Layers of the Gluteal Region:

1. Thick Skin

2. Very thick Superficial Fascia

3. Deep Fascia

4. Muscles (most of the muscles are called Gluteus)

Muscles of the Gluteal Area

a) Gluteus Maximus: largest Muscle in the body(mass and weight)

Action: Extension, Lateral Rotation of Hip & confirm the extension of

the knee joint.

Nerve supply: Inferior Gluteal Nerve

b) Gluteus Medias:

Action: Abduction of the hip (prevent tilting of the pelvis during

walking).

Nerve supply: Superior Gluteal Nerve

c) Gluteus Minimus:

Action: Abduction of the hip (prevent tilting of the pelvis)

Nerve supply: Superior Gluteal Nerve

d) Piriformis:

Action: Lateral Rotation of the Hip joint

Nerve supply: Sacral Plexus

e) Obturator Internus:

Action: Lateral Rotation of the Hip

Nerve supply: Nerve to Obturator Internus

f) Gemellus superior:

Action: Lateral Rotation of the Hip

Nerve supply: Nerve to Obturator Internus

g) Gemellus inferior:

Action: Lateral Rotation of the Hip

Nerve supply: Nerve to Quadratus Femoris

h) Quadratus Femoris:

Action: Lateral Rotation of the Hip

Nerve supply: Nerve to Quadratus Femoris

i) Tensor Fascia Lata:

Action: Confirm Extension of the knee joint.

Nerve supply: Superior Gluteal Nerve

*The Piriformis is the KEY of Gluteal Region, Most structure that passes superior to it are called

superior (Superior Gluteal VAN), and Most structure passing inferior to it are called inferior (Inferior

Gluteal VAN).

*The abdominal Aorta when it reaches L4, it divides into right common Iliac and left common iliac,

each gives External iliac which continue as Femoral Artery, and Internal iliac that will supply Pelvis.

The superior and inferior gluteal arteries are branches from the internal iliac artery.

The Posterior Compartment of the Thigh

Muscles

*All originates from Ischial Tuber.

*All supplied by Sciatic Nerve.

*All Entend the Hip.

*Most Flex the Knee.

*All Supplied by Deep Branch of Femoral Artery.

*SGS area: is the spot that (Sartorius and Gracillis and Semitendinosus) are inserted.

1. Semitendinosus.

2. Semimembranosus.

3. Biceps:

a. Long Head.

b. Short Head: only Flexes the Knee because it crosses only 1 Joint.

Sciatic Nerve:

o Origin: from ventral rami of L4, L5, S1, S2, S3, so it is originated from sacral and lumber

plexus

o Supplies: (post. Comp of thigh and leg).

o Coarse: Leaves the Pelvis through Greater Sciatic Foramen(gateway of the Pelvis), then

passes below Piriformis, then it gives 2 branches:

1) Tibial Nerve

2) Fibial Nerve (common peroneal nerve)

Popliteal fossa: It’s a diamond shaped space located behind the Knee Joint

Bounded:

SuperioMedially by: Semitendinosus and semimembranosus

SuperoLaterally by: Biceps Femoris

InferioMedially by: Medial head of Gastrocnemius

InferioLaterally by: Lateral head of Gastrocnemius

Contents: (from superficial to deep) Important

1. Small Saphenous Vein

2. Sciatic Nerve and branches

3. Popliteal Vein

4. Popliteal Artery (it is so deep so you cant measure pulse)

When you sit on a chair and you feel Numbness in your feet, it is caused by

compression of sciatic Nerve from the Popliteal Fossa.

The Neurovascular bundle here is not arranged as supposed to be (VAN, Vein,

Artery, Nerve), because here it is in a transition state, they were anterior then

became posterior.

The following table may help you in memorizing↓

The Leg I tried to make it easier by writing the information as points rather than paragraphs.

Tibia is the only weight bearing bone in the leg.

Its proximal end has 2 condyles while its distal end has medial malleolus.

Fibula is only for muscle attachments.

Tibial tuberosity is the site for the attachment of quadriceps muscle (patellar

ligament).

Anterior border & medial surface of the tibia are subcutaneous; which means you

can feel them easily.

The anterior border is called “Shin”; this is the site that all of us suffered from its

pain through childhood; when slipping one the stairs.

Shaft of the Tibia is triangular in cross section → 3 borders & 3 surfaces.

Distal end of the tibia articulates with Talus bone in the foot.

The fibula, however, articulates with the lateral condyle of the tibia.

Remember that: the neck of the fibula is a very important clinical landmark;

to be clarified later.

Posterior surface of the tibia has an oblique line called soleal line.

The ankle joint is U shaped & is formed of:

1- Lateral malleolus.

2- Medial malleolus.

3- Inferior articulating surface of tibia.

Deep fascia of leg sends 2 intermuscular septa; one anterior & the other posterior →

so the leg is divided into three compartments.

Notice that: peroneus (Latin) is the same as Fibula (Greek)

Soleus muscle gives you the initiation for running & walking.

When the Femoral artery passes the popliteal fossa; it is now called popliteal

artery.

Notice that the popliteal artery bifurcates at the lower border of the popliteus

muscle into:

1- Anterior Tibial artery (Ant. Compartment)

2- Posterior Tibial artery (Post. + Lateral compartment)

It is worth noticing that the Sciatic nerve divides into two branches:

a- Tibial nerve; which passes between the 2 heads of Gastrocnemius, to supply

the posterior compartment.

b- Common peroneal nerve (fibular nerve); which wined around the neck of

the fibula.

So, if the neck of Fibula is fractured, what might happen?

- Well, as the fibular nerve supplies the anterior & lateral compartment

through its 2 branches; loss of the function of extensors will occur.

Remember that:

- Deep Fibular Nerve supplies the Anterior Compartment.

- Superficial Fibular Nerve supplies the Lateral Compartment.

There is a tendon located posteriorly; you can easily feel it; called

Calcaneal Tendon OR Ackhilles Tendon; which is mainly made by soleus

muscle.

The importance of this tendon is that it helps in Soleal Pump; which

means to pump venous blood against gravity.

Good to know:

- That Planatris muscle has a small belly and a long tendon; yet it is

important in tendon transplant.

- Popliteus muscle, which extends from lateral to medial, causes Unlocking

of the knee; through Lateral Rotation of the femur.

- Popliteus muscle also initiates flexion of the extended knee.

The following tables summarize the action & nerve supply of the leg

muscles.

Notice that the doctor has mentioned the functions simply, yet the

book is more detailed in some of the functions.

Remember that any “Tibialis” causes Inversion (sole in)

&

any “Fibularis” causes eversion (sole out)

&

Extension of the ankle joint = Dorsi-Flexion

&

Flexion of the ankle joint = Plantar-Flexion

My students … We Are Done.

Many thanks to Dr. Ahmad Gharaibeh

GOOD LUCK TO YOU ALL

Dr. Maher Taha Hadidi