Dr. SREEKANTH THOTA

WINDSOR UNIVERSITY

SCHOOL OF MEDICINE

DEPARTMENT OF ANATOMY

Lower limbLEG

The leg is that part of the lower limb between the knee joint and ankle joint .

The leg is divided into anterior , posterior , and lateral (fibular) compartments by:

1. An interosseous membrane, which links adjacent borders of the tibia and fibula along most of their length.

2. Two intermuscular septa, which pass between the fibula and deep fascia surrounding the limb.

Fascial Compartments of the Leg

1. Muscles in the anterior compartment of leg dorsiflex the ankle, extend the toes, and invert the foot.

2. Muscles in the posterior compartment plantarflex the ankle, flex the toes, and invert the foot.

3. Muscles in the lateral compartment evert the foot.

Compartments of leg

1. Extensor retinacula :Two extensor retinacula strap the tendons of the extensor muscles to the ankle region and prevent tendon bowing during extension of the foot and toes .

1. Superior extensor retinaculum

2. Inferior extensor retinaculum: Y-shaped

Retinacula of the Ankle

Fibular (peroneal) retinacula bind the tendons of the fibularis longus and fibularis brevis muscles to the lateral side of the foot.

1. Superior fibular retinaculum

2. Inferior fibular retinaculum

Fibular retinacula

It attaches above to the medial malleolus and below and behind to the inferomedial margin of the calcaneus.

Flexor retinaculum

Muscles: The tibialis anterior, extensor digitorum longus, Fibularis tertius, and extensor hallucis longus

Blood supply: Anterior tibial arteryNerve supply: Deep peroneal nerveAction: Dorsiflex the foot at the ankle joint,

extend the toes, and invert the foot.

Anterior compartment of leg

Tibialis anterior Origin: Lateral surface of

shaft of tibia and interosseous membrane

Insertion :Medial cuneiform and base of first metatarsal bone

N. supply: Deep peroneal nerve

Action :Dorsiflexion of foot at ankle joint; inversion of foot.

Extensor digitorum longusOrigin: Anterior surface of

shaft of fibulaInsertion :Extensor

expansion of lateral four toesN. supply: Deep peroneal

nerve

Action :Extension of lateral four toes and dorsiflexion of foot

Extensor hallucis longusOrigin: Anterior surface of

shaft of fibulaInsertion :Base of distal

phalanx of great toeN. supply: Deep peroneal

nerve

Action :Extension of great toe and dorsiflexion of foot

Fibularis tertiusOrigin: Anterior

surface of shaft of fibula

Insertion :Base of fifth metatarsal bone

N. supply: Deep peroneal nerve

Action :Dorsiflexion and eversion of foot

Anterior Tibial Artery: Terminal branch of the popliteal artery.

It arises at the level of the lower border of the popliteus muscle and passes forward into the anterior compartment of the leg through an opening in the upper part of the interosseous membrane.

Artery of the Anterior Compartment of the Leg

Having passed behind the superior extensor retinaculum, it has the tendon of the extensor hallucis longus on its medial side and the deep peroneal nerve and the tendons of extensor digitorum longus on its lateral side.

In front of the ankle joint, the artery becomes the dorsalis pedis artery.

Pulse of anterior tibial artery

Deep Peroneal Nerve: Terminal branch of the common peroneal nerve .

Branches1. Muscular

branches :Tibialis anterior, the extensor digitorum longus, the peroneus tertius, and the extensor hallucis longus.

2. Articular branch to the ankle joint

Nerve Supply of the Anterior Compartment of the Leg

Footdrop and loss of eversion

May cause sensory loss over lateral leg and dorsum of foot

CausesDirect trauma as

nerve passes superficially around neck of fibula

Injury to common fibular nerve

Foot drop

Foot drop, sometimes called drop foot, is a general term for difficulty lifting the front part of the foot.

The loss of dorsiflexion of the ankle causes footdrop.

Muscles: Fibularis longus and Fibularis brevisBlood supply: Branches from the Fibular

arteryNerve supply: Superficial peroneal nerve

Lateral Compartment of the Leg

Fibularis longus Origin: Lateral

surface of shaft of fibula

Insertion :Base of first metatarsal and the medial cuneiform

N. supply: Superficial fibular nerve

Action :Eversion of foot

Fibularis brevis Origin: Lower two-

thirds of lateral surface of shaft of fibula

Insertion :Base of fifth metatarsal bone

N. supply: Superficial Fibular nerve

Action :Eversion of foot

Numerous branches from the fibular artery which lies in the posterior compartment of the leg, pierce the posterior fascial septum and supply the Fibularis muscles.

Artery of the Lateral Compartment of the Leg

Superficial Fibular Nerve: The superficial fibular nerve is one of the terminal branches of the common fibular nerve.

It arises in the substance of the Fibularis longus muscle on the lateral side of the neck of the fibula.

BranchesMuscular branches :

Fibularis longus and brevis

Nerve of the Lateral Compartment of the Leg

Loss of eversion Fibularis longus and brevis

Injury to superficial fibular nerve

Posterior compartment of leg Muscles in the

posterior (flexor) compartment of leg are organized into two groups, superficial and deep.

Blood supply: Posterior tibial artery.

Nerve supply: Tibial nerve

Muscles of the Posterior Compartment of the LegSuperficial group of

muscles1.Gastrocnemius2.Soleus3.Plantaris

Deep group of muscles1.Popliteus2.Tibialis posterior3.Flexor digitorum

longus4.Flexor hallucis

longus

Muscles mainly plantarflex, invert the foot and flex the toes.

Gastrocnemius Soleus Plantaris

Gastrocnemius and plantaris cross knee joint and thus also flex knee .

All three contribute to calcaneal tendon.

Superficial group

Origin: Lateral head from lateral condyle of femur

Medial head from above medial condyle

Insertion:Via tendo calcaneus into posterior surface of calcaneum

Innervation: Tibial nerve Function: Plantarflexes foot

and flexes knee

Gastrocnemius

PlantarisOrigin: Lateral

supracondylar ridge of femur

Insertion: Posterior surface of calcaneum

Innervation: Tibial nerve

Function: Plantarflexes foot and flexes knee

SoleusOrigin: Shafts of tibia

and fibulaInsertion: Posterior

surface of calcaneumInnervation: Tibial nerve Function: Plantarflexes

the foot

Deep group of muscles

Popliteus

Origin: Lateral surface of lateral condyle of femur

Insertion: Posterior surface of shaft of tibia above soleal line

Innervation: Tibial nerve Function: Flexes leg at knee

joint

“Unlock the knee” popliteus contracts rotating the femur laterally so that flexion of the knee can occur

Flexor digitorum longusOrigin: Posterior surface of

shaft of tibiaInsertion: Bases of distal

phalanges of lateral four toesInnervation: Tibial nerve Function: Flexes distal

phalanges of lateral four toes; plantar flexes foot at ankle joint

Origin: Posterior surface of shaft of fibulaInsertion: Base of distal phalanx of big toeInnervation: Tibial nerve Function: Flexes distal phalanx of big toe;

plantar flexes foot at ankle joint

Flexor hallucis longus

Origin: Posterior surface of shafts of tibia and fibula and interosseous membrane

Insertion: Tuberosity of navicular boneInnervation: Tibial nerve Function: Inversion and plantarflexion of

foot

Tibialis posterior

Tibial nerve:Supplies all muscles in posterior compartment.

Divides into medial and lateral plantar nerves inferior and posterior to medial malleolus.

Nerve supply

Posterior tibial artery:Largest branch of popliteal artery.Divides into medial and lateral plantar

arteries.Fibular artery:Most important branch of posterior tibial artery.Supplies lateral compartment.

Blood supply:

Arteries in the posterior compartment of leg.

Tarsal tunnelThe 'tarsal tunnel' is formed on the

posteromedial side of the ankle by a depression formed by the medial malleolus of the tibia, the medial and posterior surfaces of the talus, the medial surface of the calcaneus and overlying flexor retinaculum.

Contents of Tarsal tunnelStructures That Pass

Behind the Medial Malleolus Beneath the Flexor Retinaculum From Medial to Lateral

1.Tibialis posterior tendon2.Flexor digitorum longus3.Posterior tibial artery4.Tibial nerve5.Flexor hallucis longus( TOM DICK AND HARRY)

Tibial Nerve Entrapment Tarsal tunnel syndrome Tarsal tunnel syndrome is caused

by compression of the tibial nerve in the canal formed by the flexor retinaculum and the foot bones.

Causes: 1. Tenosynovitis (swelling of the

synovial membrane lining the tendons) 2. Fractures of the talus, tibia or

calcaneum bones Symptoms Abnormal sensation such as tingling

and numbness in the sole or toes Treatment non-operative and

operative.

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Posterior Tibial Pulse

The posterior tibial pulse can usually be palpated between the posterior surface of the medial malleolus and the medial border of the calcaneal tendon.