Leg

Dr. Heba Kalbouneh

Associate Professor of Anatomy and Histology

Medially:

The saphenous nerve, a branch of the

femoral nerve supplies the skin on the

medial surface of the leg

Laterally:

Upper part

The lateral cutaneous nerve of the calf, a

branch of the common fibular nerve supplies

the skin on the upper part of the lateral

surface of the leg

Skin of the Leg

Posteriorly:

The posterior cutaneous nerve of the

thigh supplies the skin over the

popliteal fossa and the upper part of the

back of the leg

Cutaneous Nerves

Laterally:

Lower part

Anterolaterally

The superficial fibular nerve, a terminal

branch of the common fibular nerve

supplies the skin on the lower part of the

anterolateral surface of the leg

Posterolaterally

The sural nerve, a branch of the tibial nerve

supplies the skin on the lower part of the

posterolateral surface of the leg

Fascial Compartments of the Leg

The deep fascia of the leg forms Two

intermuscular septa

(anterior and posterior) which are

attached to the fibula

These, together with the interosseous

membrane divide the leg into:

Three compartments:

Anterior

Lateral

Posterior

Each having its own muscles, blood

supply, and nerve supply.

Sciatic nerve

Tibial nerve Common fibular nerve

Superficial

fibular nerve

Deep

fibular nerve

Posterior compartment

of leg

Anterior compartment

of leg

Lateral compartment

of leg

Superior

Extensor

Retinaculum Inferior

Extensor

Retinaculum

Retinacula of the Ankle

The retinacula are thickenings of the deep

fascia that keep the long tendons around the

ankle joint in position and act as pulleys.

Superior Extensor Retinaculum

Inferior Extensor Retinaculum

Superior Fibular Retinaculum

Inferior Fibular Retinaculum

Flexor Retinaculum

Anterior view

Superior Extensor

Retinaculum

between tibia and fibula

above the malleoli Inferior Extensor

Retinaculum

Y-shaped band located in front

of the ankle joint.

Originates from calcaneus

separates into two bands:

Upper: passes to the medial

malleolus

Lower: to the navicular and

medial cuneiform bones

Anterior view

Flexor Retinaculum

Extends from medial malleolus to calcaneus

Posterior view

Superior Fibular

Retinaculum

Inferior Fibular Retinaculum

Posterior view

Popliteal artery

Anterior tibial artery

Posterior tibial artery

Popli

teus

Posterior view

Anterior tibial artery passes

forward through an opening

in the upper part of the

interosseous membrane and

enters the anterior

compartment of the leg.

It continues onto the dorsal

aspect of the foot

Posterior view

Ant view

Anterior tibial artery

Fibular artery

Posterior tibial artery

Popliteal artery

Posterior tibial artery

Posterior view

Supplies posterior and

lateral compartments of

the leg and continues into

the sole of the foot

Is a branch from posterior

tibial artery and runs parallel

to it, it supplies the posterior

and lateral compartments of

the leg

Tibial nerve

Common fibular nerve

Popliteal artery

Popliteal vein

Posterior view

Superficial fibular nerve

Supplies the muscles of the lateral

compartment of the leg

Deep fibular nerve

Supplies the muscles of

the anterior compartment

of the leg

Anterior view

Tibial nerve

Supplies the muscles of the

posterior compartment of the

leg

Posterior view

Cross section in the shaft of fibula

Late

ral

su

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ce

Provides origin to

The muscles of the

lateral

compartment of the leg

Provides origin to some

of the posterior

compartment of the leg

(Flexor surface)

Provides origin to

the anterior compartment of the

leg

(Extensor surface)

Muscles:

Tibialis anterior

Extensor digitorum longus

Extensor hallucis longus

Fibularis (Peroneus) tertius

Blood supply: Anterior tibial artery

Nerve supply: Deep fibular (peroneal) nerve

Anterior Fascial Compartment of the Leg

Action: All dorsiflex of the foot.

Hallucis: Extends big toe

Digitorum : Extends four toes

Tibialis: Inverts of the foot

Fibularis: Everts of the foot

All the muscles of the anterior compartment of the leg originate from

fibula EXCEPT Tibialis anterior from Tibia.

The main actions of these muscles are:

Extension of the foot at the ankle joint (dorsiflextion) to raise the toes up

(in other words to stand up on the heels)

In addition any muscle that got (tibialis) in its name

Inverts the foot at subtalar and transverse tarsal joints

while any muscle got (fibularis/ peroneus) in its name

Everts foot at subtalar and transverse tarsal joints

Nerve supply of all the muscles of the anterior compartment of the leg:

Deep fibular nerve

Insertion?

Tibialis anterior

Origin: lateral surface of shaft

of tibia and interosseus

membrane

Insertion: medial cuneiform

and base of first metatarsal

bone

Nerve supply: Deep fibular

nerve

Action: dorsiflexion of foot at

ankle joint, inversion of foot at

subtalar and transverse tarsal

joints, holds up medial

longitudinal arch of foot

Extensor hallucis longus

Origin: anterior surface of

shaft of fibula

Insertion: base of distal

phalanx of big toe

Nerve supply: Deep fibular

nerve

Action: extends big toe,

dorsiflexion of foot at ankle

joint

Extensor digitorum longus

Origin: anterior surface of

shaft of fibula and extends

superiorly onto the lateral

condyle of tibia

Insertion: via extensor

expansion into bases of middle

and distal phalanges of lateral

four toes

Nerve supply: Deep fibular

nerve

Action: extends toes,

dorsiflexion of foot at ankle

joint Fibularis tertius is

considered part of

extensor digitorum longus

and inserts into the base

of 5th metatarsal

Action: dorsiflexion and

eversion

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FROM MEDIAL TO LATERAL

In front of the medial malleolus

Anterior

tibial

artery

Tibialis anterior

Extensor Hallucis longus

Extensor

Digitorum

Anterior tibial artery Deep fibular nerve

Medial Lateral

Note: The two extensor

retinacula hold the tendons of the

extensor muscles in place and

prevent bowing during extension

of the foot and toes

Lateral Fascial Compartment of the Leg

Muscles:

Fibularis longus

Fibularis brevis

Nerve supply: Superficial fibular nerve

Blood supply: Branches from the fibular artery

(branch from posterior tibial artery)

Fibularis

brevis

Fibularis

longus

Fibularis longus:

Origin: Lateral surface of

shaft of fibula

Insertion: Base of first

metatarsal and the medial

cuneiform bone

Nerve supply: Superficial

fibular nerve

Action: Plantar flexes the foot

at the ankle joint, everts the

foot at the subtalar and

transverse tarsal joints,

supports lateral longitudinal

and transverse arches of foot

Fibularis brevis:

Origin: Lateral surface of shaft

of fibula

Insertion: Base of fifth

metatarsal bone

Nerve supply: Superficial fibular

nerve

Action: Plantar flexes the foot at

the ankle joint, everts the foot at

the subtalar and transverse tarsal

joints, supports lateral

longitudinal arch of foot

Superior and inferior

fibular retinacula bind the

tendons of fibularis longus

and brevis as they pass from

the lateral compartment of the

leg into the lateral side of the

foot

Posterior Fascial Compartment of the Leg

Superficial group of

muscles

Gastrocnemius

Plantaris

Soleus

Deep group of muscles

Popliteus

Flexor digitorum longus

Flexor hallucis longus

Tibialis posterior

Blood supply: Posterior tibial artery

Nerve supply: Tibial nerve

In the posterior compartment, a transverse septum further

divide the posterior compartment into layers of superficial

and deep muscles

Gastrocnemius

Origin: Lateral head from lateral condyle of

femur

Medial head from above medial condyle

Insertion: Via calcaneal tendon into

posterior surface of calcaneus

Nerve supply: Tibial nerve

Action: Plantar flexes foot at ankle joint,

Flexes knee joint

Superficial group of muscles (Posterior compartment of leg)

Plantaris

This muscle sometimes is absent

Origin: Lateral supracondylar ridge of femur

Insertion: Posterior surface of calcaneus

Nerve supply: Tibial nerve

Action: Plantar flexes foot at ankle joint,

Flexes knee joint

Superficial group of muscles (Posterior compartment of leg)

Soleus

Origin: Shafts of tibia (soleal line) and

fibula

Insertion: Via calcaneal tendon into

posterior surface of calcaneus

Nerve supply: Tibial nerve

Action: Together with gastrocnemius is

powerful plantar flexor of ankle

joint; provides main propulsive force in

walking and running

Superficial group of muscles (Posterior compartment of leg)

As a unit, these muscles are large and

powerful because they propel the body

forward off the planted foot during walking

and can elevate the body upward onto the

toes when standing

Deep group of muscles

(Posterior compartment of leg)

Popliteus

Origin: lateral surface of

lateral condyle of femur (popliteal groove)

Insertion: posterior surface of

of tibia above soleal line

Nerve supply: Tibial nerve

Action: flexes leg at knee

joint, unlocks the extended

knee at the initiation of flexion

by lateral rotation of femur on

tibia, medial rotation of tibia,

and slackens ligaments of knee

joint

Unlocking means Lateral

rotation of the femur

Or Medial rotation of the

tibia

Locking means…………..

rotation of the femur Or

…………rotation of the

tibia

Deep group of muscles

(Posterior compartment of leg)

Tibialis posterior

Origin: posterior surface of

tibia and fibula and

interosseous membrane

Insertion: tuberosity of

navicular bone and other

neighboring bones

Nerve supply: Tibial nerve

Action: plantar flexes foot at

ankle joint, inversion of foot at

subtalar and transverse tarsal

joints, supports medial

longitudinal arch of foot

Deep group of muscles

(Posterior compartment of leg)

Flexor digitorum longus

Origin: posterior surface of

tibia

Insertion: bases of distal

phalanges of lateral four toes

Nerve supply: Tibial nerve

Action: flexes distal

phalanges of lateral four toes,

plantar flexes foot at ankle

joint, supports medial and

lateral longitudinal arches of

foot

Flexor hallucis longus

Origin: posterior surface of

fibula

Insertion: base of distal

phalanx of big toe

Nerve supply: Tibial nerve

Action: flexes distal phalanx

of big toe, plantar flexes foot

at ankle joint, supports medial

longitudinal arch of foot

Deep group of muscles

(Posterior compartment of leg)

Behind the medial malleolus

From Anterior to Posterior

Tibialis posterior

Flexor digitorum

longus

Posterior tibial vessels

Tibial nerve

Flexor hallucis longus

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Tarsal tunnel is formed on the posteromedial side of the ankle

and covered by flexor retinaculum

Provides channels for the tendons of flexor muscles as they pass from the posterior

compartment of the leg into the sole of the foot

Surface anatomy

Popliteal Fossa

Dr. Heba Kalbouneh

Associate Professor of Anatomy and Histology

Is a diamond-shaped intermuscular space

situated at the back of the knee

Boundaries

Laterally:

Above

Biceps femoris

Below

Lateral head of gastrocnemius and Plantaris

Medially:

Above

Semimembranosus and semitendinosus

Below

Medial head of gastrocnemius

Popliteal Fossa

Lateral

The floor (anterior wall) of the

fossa is formed by:

Popliteal surface of the femur

Capsule of the knee joint

Popliteus muscle

The roof is formed by:

Skin

Superficial fascia

Deep fascia

Contents of popliteal fossa:

1- Popliteal artery

2-Popliteal vein

3- Common fibular nerve (lateral popliteal nerve)

4- Tibial nerve

(medial popliteal nerve)

5- Small saphenous vein

(termination)

6- Connective tissue

7- Lymph nodes

Popliteal artery

Popliteal vein

Tibial nerve

Common

fibular nerve

Small

saphenous

vein

At the middle of the fossa

The popliteal artery is the deepest structure

While the vein is intermediate

and the tibial nerve is most superficial

Enters the popliteal fossa through the

adductor hiatus as a continuation of the

femoral artery

The deepest structure in the fossa

It ends at the level of the lower border

of the popliteus muscle by dividing into

anterior and posterior tibial arteries

Gives genicular branches to knee joint

Popliteal artery

Anterior tibial artery

Posterior tibial artery

Popli

teus

Femoral

artery

When examining a lump in the popliteal region, think of these possibilities:

Skin and soft tissues—sebaceous cyst, lipoma

Vein—varicosities of the short saphenous vein in the roof of the fossa

Artery—popliteal aneurysm

Lymph nodes—infection secondary to suppuration in the foot

Knee joint—joint effusion

Tendons—enlarged bursae, especially those beneath semimembranosus

and the heads of gastrocnemius

Bones—a tumour of the lower end of femur or upper end of tibia

The popliteal fossa is a good example of the value of thinking

anatomically when considering the differential diagnosis of

a mass situated in a particular anatomical area.

A baker’s cyst (or popliteal cyst)

refers to the inflammation and

swelling of the

semimembranosus bursa

Tibial

nerve

Sciatic nerve

Common

fibular

nerve

Origin :

From sciatic nerve at the lower third of the

thigh

Course:

It enters popliteal fossa from upper angle

and leaves it at its lower angle to enter the

posterior compartment of the leg

Termination:

It ends deep to flexor retinaculum by

dividing into medial and lateral plantar

nerves.

Tibial nerve

Femoral

vein

Femoral

artery

Sural

nerve

Small

saphenous

vein

Sural nerve Small saphenous

vein

Sural nerve

Supplies skin on

posterolateral side of lower part

of leg and lateral side of foot

The sural nerve accompanies

the small saphenous vein

behind the lateral malleolus

The small saphenous

vein pierces the

popliteal fascia to empty

into the popliteal vein

The sural nerve pierces

the deep fascia

The small saphenous vein

Starts at the lateral side of the

dorsal venous arch in the foot

Passes behind the lateral

malleolus

Ascends vertically in the

superficial fascia on the back of

the leg

Penetrates the deep fascia at the

back of the knee

Drains into popliteal vein

Tibial nerve

Sciatic nerve

Popli

teus

Tibial nerve enters the

posterior compartment of

the leg by passing beneath

the soleus muscle

Medial plantar nerve

Lateral plantar nerve

Tibial nerve

Sural

Medial

calcaneal

Saphenous

Medial

plantar

Lateral

plantar

Medial

calcaneal nerve

(Tibial nerve)

(Tibial nerve)

(Tibial nerve)

(Tibial nerve)

Muscular Sensory

All muscles in posterior compartment of thigh (except

short head of biceps), all muscles in posterior

compartment of leg, most intrinsic muscles of the foot

Sural nerve:

Supplies skin on posterolateral side

of lower part of leg and lateral side

of foot

Medial calcaneal branch:

Supplies the skin over the medial

surface of the heel.

Medial plantar nerve: sensory to

Medial 2/3 of sole and medial

three and a half toes.

Lateral plantar nerve: sensory to

Lateral 1/3 of sole and lateral one

and a half toes

Also

Motor to most intrinsic muscles

of the foot

Tibial nerve injury

Motor Sensory

Paralysis of all muscles in the posterior

compartment of the leg

Paralysis of most intrinsic foot muscles

Loss of plantar-flexion at the ankle

Weakness of inversion

Foot is dorsiflexed and everted

Sensory loss from:

Posterolateral side of lower part of leg

Sole of the foot

Injury to tibial nerve

Because of its deep and protected position, its rarely

injured

Complete damage results in:

Paralysis of all muscles in the back of the leg and

most intrinsic muscles of the foot

The anatagonistic muscles (dorsiflexors and evertors)

will take over leading to an attitude called:

(Calcaneovalgus)

Foot is dorsiflexed and

everted

Tibial nerve

Sciatic nerve

Common

fibular

nerve

Origin:

From sciatic nerve at the lower third of the

thigh

Course:

It descends from the superior to the lateral

angle of the popliteal fossa close to the medial

border of biceps femoris.

Termination:

It ends at the neck of fibula where it divides

into superficial and deep fibular nerves

Branches:

Common fibular nerve

Muscular Sensory

Short head of

biceps femoris

1- Sural communicating

branch

2- Lateral cutaneous nerve

of the calf: supplies the skin

on the upper part of the

lateral side of the leg

Lateral

cutaneous nerve

of the calf

Lateral

cutaneous nerve

of the calf

Superficial

fibular nerve

Muscular Sensory

Muscles of anterior

compartment of leg

Some of the intrinsic muscles of

foot

Skin between big toe and

second at dorsum of foot

Muscular Sensory

Muscles of lateral

compartment of leg

Supplies skin on

anterolateral side of

lower part of leg

Supplies skin of

intermediate part of

dorsum of foot

Superficial fibular nerve

Deep fibular nerve

Superficial

fibular

nerve

Deep

fibular

nerve

Common

fibular

nerve

The superficial fibular

nerve

Also called the

musclocutaneous

nerve of the leg

Supplies two muscles in

the lateral compartment

of the leg and then

becomes cutaneous

where it supplies the

skin over the

anterolateral side of

lower part of leg and the

intermediate part of

dorsum of foot

(except the cleft of skin

between the 1st and 2nd

toes)

Common fibular nerve injury Cause: most common cause is fracture neck of fibula

Motor Sensory

Paralysis of muscles of the anterior and

lateral compartments of the leg

Loss of dorsiflexion at the ankle

Foot drop

Loss of eversion

Inversion of the foot is weakened

Foot is plantarflexed and inverted

Sensory loss from:

Anterolateral side of lower part of leg

Intermediate area of dorsum of foot

Dorsum of the toes except the lateral side of

the little toe

Foot drop

Common fibular nerve is in an exposed position as it

leaves the popliteal fossa and winds around the neck

of fibula

Injury to common fibular nerve

Paralysis of extensor muscles (supplied by deep

fibular nerve)

This means loss of dorsiflexion of the foot

Paralysis of fibularis muscles (supplied by

superficial fibular nerve)

This means loss of eversion of the foot

The anatagonistic muscles (plantar-flexors and

invertors) will take over leading to an attitude called:

(Equinovarus)

Foot drop and inversion

Injury to common fibular nerve

Plantarflexion (Foot drop) and inversion

of foot

Injury to superficial fibular nerve

Inversion of foot

Injury to deep fibular nerve

Plantarflexion (Foot drop)

Injury to tibial nerve

Dorsiflexiom and eversion of foot

Saphenous nerve

Deep fibular nerve

Lat cutaneous

nerve of the calf

Superficial fibular nerve

Deep fibular nerve

Lat cutaneous nerve

of the calf

Superficial fibular nerve Sural nerve

Lat cutaneous nerve

of the calf

Medial calcaneal nerve

Sural nerve

Saphenous nerve

Post cutaneous nerve

of the thigh