Slideshow: Posterior Leg

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Posterior Leg Compartment

The posterior compartment of the leg contains flexor muscles that plantarflex the ankle joint

There is a Superficial Posterior Compartment and aDeep Posterior Compartment

There are 3 muscles in the Superficial Compartment

•Gastrocnemius

•Plantaris

•Soleus

There are 4 muscles in the Deep Compartment

•Popliteus

•Flexor Digitorum Longus

•Flexor Hallucis Longus

•Tibialis Posterior

Cross Section through middle of right leg looking up from foot

anterioranterior

posteriorposterior

LATERAL

MEDIAL

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIAL

Septum

Interosseous membrane

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIAL

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIAL

Anterior Compartment

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIAL

Lateral Compartment

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIAL

Lateral Compartment

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIAL

Lateral Compartment

Deep PosteriorCompartment

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIAL

Superficial Posterior Compartment

Lateral Compartment

Muscles of the Superficial Posterior

Compartment

Gastrocnemius

GastrocnemiusArises as two heads from the posterior surface of the

Medial and Lateral Femoral Condyles

Posterior view, right leg

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIALLateral

Compartment

GastrocnemiusGastrocnemiusMedial HeadMedial Head

GastrocnemiusGastrocnemiusLateral headLateral head

Soleus

Originates from the •posterior aspect of the fibular head •Fibular shaft•Tibial shaft

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIALLateral

Compartment

GastrocnemiusGastrocnemiusMedial headMedial head

SoleusSoleus

Soleus and Gastrocnemiusmerge to form the Achilles tendon

This tendon inserts onto the posterior and superior surfaces of the Calcaneum

Plantaris

This slender muscle arises from the Lateral Supracondylar ridge of the Femur

and inserts onto the Calcaneum just medial to the Achilles Tendon

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIAL

Deep PosteriorCompartmentLateral

Compartment

SoleusSoleus

PlantarisPlantaris

Muscles of the Deep Posterior Compartment

Popliteus

Originates from the posterior aspect of the upper Tibia

Popliteus

Inserts onto lateral surface of lateral condyle of Femur

Popliteus

This muscle contributes to the function of the knee joint by unlocking the extended leg and

rotating the Femur on the Tibia

Inserts onto lateral surface of lateral condyle of Femur

Tibialis Posterior

Originates from the posterior aspects of the•Interosseous membrane•Fibular shaft •Tibial shaft

Tibialis Posterior

Inserts onto the Navicular, and sends extensions to other tarsal bones and metatarsals

Originates from the posterior aspects of the•interosseous membrane•fibular shaft •tibial shaft

Tibialis Posterior

This is the principal invertor of the foot

Inserts onto the navicular, and sends extensions to other tarsal bones and metatarsals

Originates from the posterior aspects of the•interosseous membrane•fibular shaft •tibial shaft

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIALLateral

Compartment

SoleusSoleus

PlantarisPlantaris

Tibialis PosteriorTibialis Posterior

Originates from the posterior aspect of theTibial shaft

Flexor Digitorum Longus

Originates from the posterior aspect of theTibial shaft

Splits into 4 tendons which insert onto the distal phalanges of toes 2-5

Originates from the posterior aspect of thetibial shaft

Flexes the toes

Splits into 4 tendons which insert onto the distal phalanges of toes 2-5

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIALLateral

Compartment

SoleusSoleus

PlantarisPlantaris

Tibialis PosteriorTibialis Posterior Flexor Digitorum Flexor Digitorum LongusLongus

Flexor Hallucis LongusOriginates from the posterior aspect of theFibular shaft and Interosseous Membrane

Inserts onto the distal phalanx of the big toe

Flexor Hallucis LongusOriginates from the posterior aspect of theFibular shaft and Interosseous Membrane

Inserts onto the distal phalanx of the big toe

Flexes the big toe

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIALLateral

Compartment

SoleusSoleus

PlantarisPlantaris

Flexor Hallucis LongusFlexor Hallucis Longus

Nerve Supply

All the muscles of the Posterior Compartment of the Leg

are supplied by the

Tibial Nerve

a terminal branch of the Sciatic Nerve

Fibula

anterioranterior

posteriorposterior

LATERAL

MEDIALLateral

Compartment

SoleusSoleus

PlantarisPlantaris

Flexor Hallucis LongusFlexor Hallucis Longus

Tibial Nerve

Summary of Muscles

GastrocnemiusOrigin Medial head: posterior surface of

medial femoral condyleLateral head: posterior surface of lateral femoral condyle

Insertion The two heads unite and with soleus form the Achilles tendon, which inserts onto the posterior and upper surface of calcaneum

Action Powerful plantar flexor of ankle

Nerve Supply Tibial nerve ( S1, S2)

Blood Supply Sural branches of the popliteal artery

Posterior Leg

SoleusOrigin Posterior aspect of fibular head,

posterior surface of upper fibular shaft, soleal line on posterior tibia and medial border of tibia

Insertion unites with gastrocnemius aponeurosis to form the Achilles tendon, inserts onto posterior and upper surfaces of calcaneum

Action Plantar flexor of ankle

Nerve Supply Tibial nerve (S1, S2)

Blood Supply Posterior tibial, peroneal, and sural arteries

Posterior Leg

PlantarisOrigin Inferior aspect of lateral

supracondylar ridge of distal femur

Insertion Posterior calcaneal surface, medial to Achilles tendon

Action Plantar flexor of ankle; also flexes knee

Nerve Supply Tibial nerve (L5, S1, S2)

Blood Supply Sural arteries

Posterior Leg

PopliteusOrigin Posterior surface of tibia,

superior to soleal lineInsertion Lateral surface of lateral condyle

of femur.The tendon passes into the capsule of the knee and gives an extension to posterior part of lateral meniscus

Action Unlocks the extended knee by laterally rotating the femur on the tibia.

Nerve Supply Tibial nerve (L4, L5, S1)Blood Supply Medial inferior genicular branch

of popliteal artery, posterior tibial artery

Posterior Leg

Tibialis PosteriorOrigin Posterior aspect interosseous

membrane, superior half of tibia and medial posterior surface of fibula

Insertion Inserts onto navicular tuberosity and sends extensions to other tarsal bones and metatarsals

Action Inverts, adducts, supinates foot, plantar flexes ankle

Nerve Supply Tibial nerve (L4, L5)

Blood Supply sural, peroneal and posterior tibial arteries

Posterior Leg

Flexor Digitorum LongusOrigin Posterior surface of tibia distal to

soleal lineInsertion Splits into four slips, inserts onto

plantar surface of bases of distal phalanges of 2nd-5th toes

Action Flexes toes 2 - 5; also helps in plantar flexion of ankle

Nerve Supply Tibial nerve (S1, S2) Blood Supply Muscular branches of posterior

tibial artery

Posterior Leg

Flexor Hallucis LongusOrigin Inferior 2/3 of posterior surface

of fibula, lower part of interosseous membrane

Insertion Plantar surface of base of distal phalanx of great toe

Action Flexes great toe, supinates ankle, weak ankle plantar flexor

Nerve Supply Tibial nerve (S2, S3)Blood Supply Muscular branches of peroneal

and posterior tibial artery

Posterior Leg

Slideshow: Posterior Leg

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