MOB TCD

Anterior and Lateral and Posterior Compartments of Calf

Professor Emeritus Moira O’Brien

FRCPI, FFSEM, FFSEM (UK), FTCD

Trinity College

Dublin

Cutaneous Supply of Calf

• Saphenous first branch is infrapatellar branch it

• Supplies medial side of the calf and

• Medial side of foot to ball of the hallux

• Lateral cutaneous of calf• Superficial peroneal• Sural, lateral border of foot• Deep peroneal first cleft

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Fascial Compartments in Calf

• Subcutaneous surface of tibia• Fascia anterior and posterior

intermuscular septa• Anterior compartment• Lateral compartment• Posterior compartment

Divided• Superficial• Deep• Deep posterior

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Extensor Retinacula

• Superior retinaculum • Thickening deep fascia• Tibialis anterior pierces • Other tendons pass posterior• Inferior extensor retinaculum• Inferior stem attached to calcaneus• Upper limb to medial malleolus• Lower limb plantar aponeurosis

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Anterior Compartment of Calf

• Tibialis anterior• Extensor hallucis longus• Extensor digitorum longus • Peroneus tertius• All muscles supplied by the

deep peroneal nerve• Dorsi flexors• Anterior tibial and

perforating peroneal arteries

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Tibialis Anterior

• Upper two thirds• Lateral surface of tibia and

adjoining area of interosseous membrane

• And deep fascia

Inserted• Medial aspect of medial

cuneiform• And adjoing base of first

metatarsal

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• Synovial sheath• Passes under superior and

both limbs of inferior extensor retinaculum

• Dorsi flexor and invertor• Eccentric pays out, prevents

foot slapping down• Supports medial arch• Deep peroneal nerve

Tibialis Anterior MOB TCD

Extensor Hallucis Longus

• Middle two fourths• Anterior surface of fibula • Interosseous membrane• Base of distal phalanx of

hallux• Dorsiflexor big toe and

ankle• Deep peroneal nerve• Test for L5

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• Upper three quarter anterior surface of fibula

• Except the area for the extensor hallucis longus

• Anterior intermuscular septum

• Passes under retinacula• Divides into four tendons• Joined by slips from brevis• Lumbricals and interossei

muscles

Extensor Hallucis Longus MOB TCD

Extensor Digitorum Longus

• Main extensor tendon inserted into base of middle phalanx, of the lateral four toes

• Collateral slips formed by lumbricals and interossei inserted into distal phalanx

• Dorsiflexor ankle • Extends proximal phalanx lateral four

toes

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Peroneus Tertius

• Lower quarter of anterior surface of the fibula

• Inserted into base and dorsum of shaft of fifth metatarsal

• Dorsiflexor and evertor

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Extensor Digitorum Brevis

• Fleshy origin from calcaneus • Stem of inferior retinaculum • Divides into four tendons• First is extensor hallucis brevis • Other three join extensor

expansion of second, third and fourth toes

• Deep peroneal nerve

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Deep Peroneal Nerve

• Branch of the common peroneal at neck of fibula

• Pierces anterior intermuscular septum• Runs between extensor digitorum longus and

tibialis anterior• Then tibialis anterior and extensor hallucis

longus

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• In anterior compartment• Supplies• Tibialis anterior• Extensor hallucis longus• Extensor digitorum longus • Peroneus tertius• Extensor digitorum brevis• Skin first cleft

Deep Peroneal Nerve MOB TCD

Anterior Tibial Artery

• Branch of popliteal• Enters above interosseous

membrane• Only supply of tibialis

anterior• Becomes dorsalis pedis at

ankle joint

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Dorsalis Pedis

• Gives off• First dorsal metatarsal artery• Arcuate artery gives off• 2-4th dorsal metatarsal

arteries• At base of first

intermetatarsal space• Enters sole of foot• Joins lateral plantar artery to

complete plantar arch

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Blood Supply of Dorsum

• Arcuate artery• Dorsal metatarsal arteries• Posterior and anterior perforating

branches from metatarsals• Communicate plantar arch• And its digital branches• Perforating veins drain into dorsal

venous arch

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Perforating Peroneal Artery

• Perforating peroneal artery• Pierces interosseus membrane• Enters anterior compartment• May replace dorsalis pedis

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Venous and Lymph Drainage of Foot

• Dorsal venous arch• Medial, long saphenous

vein • Anterior to medial

malleolus• Short saphenous vein• Posterior to lateral

malleolus• Lymphatics follow

superficial veins

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Lateral Compartment of Calf

• Between anterior and posterior intermuscular septa

• Peroneus longus• Peroneus brevis

• Superficial peroneal nerve

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Peroneus Longus

• Upper two thirds lateral surface of fibula • Adjoining area of interosseous

membrane• Passes under superior and inferior

peroneal retinaculum

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• May have a sesamoid bone• Runs in groove in the cuboid• Inserted into• Lateral aspect of medial cuneiform• And adjoing base of first metatarsal

Peroneus Longus MOB TCD

• Plantar flexor and evertor • Supports lateral arch• Superficial peroneal nerve• Cuboid syndrome• Torn peroneal retinacula• Snapping tendons

Peroneus Longus MOB TCD

Peroneus Brevis

• Lower two thirds• Lateral surface of fibula in front of

longus• Passes under superior and inferior

peroneal retinacula• Above peroneal trochlea on calcaneus• Inserted into base of fifth metatarsal

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Peroneus Longus and Brevis

• Plantar flexors and evertors

• Longus support the lateral longitudinal arch

• Superficial peroneal nerve

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Superficial Peroneal Nerve

• Branch common peroneal• Neck of fibula• Supplies peroneus longus and brevis • Pierces deep fascia• Dorsum of foot supplies• Medial side of big toe • All clefts except first and lateral side of little

toe

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Sensory Supply to Posterior Aspect of Calf

• Posterior cutaneous nerve of thigh• Lateral cutaneous of calf• Sural nerve• Saphenous nerve• Medial calcaneal

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Dermatomes MOB TCD

Posterior Surface of the Calf

• Short saphenous vein• Posterior to lateral malleolus

pierces the roof of popliteal fossa to enter popliteal vein

• Deep fascia thickened medial between medial malleolus and calcaneum

• Bursa anterior to achilles

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Medial and Lateral Heads of Gastrocnemii

• Medial head arises from popliteal surface of femur above medial condyle

• Lateral is shorter, arises from posterior part of the lateral surface of the lateral femoral condyle and capsule of knee

• Fabella is a sesamoid bone in lateral head

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• Bursa deep to the two heads • Medial belly is longer• Unite to form a tendinous raphe• Unites with soleus to form achilles• Fast twitch fibres• Flex knee and plantar flex ankle

Medial and Lateral Heads of Gastrocnemii

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Plantaris

• Short fleshy origin from • The popliteal surface of femur

above the lateral femoral condyle

• Long tendon passes between gastronemii and soleus

• Inserted medial border of achilles

• Tibial nerve

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• May be absent• May rupture• Used in tendon grafts• Sudden dorsiflexion

of ankle• Ballet dancing • Gymnastics• Basketball• Sprinting

Plantaris MOB TCD

Soleus

• Broad flat pennate muscle• Arises from head and upper

fourth of posterior surface of the fibula

• Fibrous arch• Soleal line of tibia• Middle third of medial border of

tibia

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• Two aponeurotic lamellae • Bulk of vascular multipennate muscle fibres• Deepest of achilles• Slow twitch fibres• Perforating veins from great saphenous enter

soleus• Acts as a peripheral pump

Soleus MOB TCD

Achilles Tendon

• Extent of the fusion between the gastronemii and soleus varies

• Inserted into middle of posterior surface of the calcaneus

• Tendon twists• Gastronemii form the lateral and posterior

part of the tendon

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• Rotation occurs above where the soleus tends to join

• Rotation is greater if minimal fusion

• Stress marked 2-5 cm above insertion

• Plantar flexor of ankle• Eccentric lower heels

Achilles Tendon MOB TCD

• The achilles tendon is subjected to the highest loads in the body

• Tensile loads up to eight and ten times body weight are experienced during running jumping hopping and skipping

• The achilles tendon is subjected to stress when running up and downhill

• A tight achilles tendon also limits dorsiflexion of the ankle

Achilles Tendon MOB TCD

• Superficial bursa may be found posterior to achilles between it and the deep fascia

• The retrocalcaneal bursa is just proximal to the insertion

• Between the tuberosity on the posterior surface of the calcaneus and the achilles tendon

Achilles Tendon MOB TCD

Achilles Test MOB TCD

Medial and Lateral Heads of Gastrocnemii

• Sprinting• Jumping• Hopping• Skipping• Stretched with knee

extended and ankle dorsiflexed

• Tibial nerve

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The Retrocalcaneal Bursa

• The area of fibro cartilage on the tendon forms the posterior wall

• The anterior wall of the retrocalcaneal bursa is the 0.5 to 1 mm thick cartilaginous layer on the posterior aspect of the calcaneus

• The proximal wall of the synovial lined sac consists of folds, or villus synovial projections

• Allows alterations in its form, produced by varying degrees of pressure on the fat above it during flexion and extension of the ankle

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Flexor Digitorum Longus

• Posterior surface of tibia • Below soleal line• Medial to vertical line• Variable origin by an

aponeurosis from fibula

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Very extensive fibular origins of FDL

FHL

Fibular origin of FDL

FDL

Hislop M, 2003

Flexor Digitorum Longus MOB TCD

• Crosses tibialis posterior in calf• Flexor hallucis longus in foot• Foot receives insertion flexor accessorius

and two slips from flexor hallucis longus• Divides four tendons• Give origin to four lumbricals

Flexor Digitorum Longus MOB TCD

• In the foot the tendon passes through birfurcation of brevis

• Inserted into distal phalanges• Plantar flexes ankle• Plantar flexes lateral four toes• Supports medial arch• Tibial nerve

Flexor Digitorum Longus MOB TCD

Flexor Hallucis Longus

• Bulkiest and most powerful, multipennate

• Arises from posterior surface of fibula

• Posterior to medial crest• Beef to heel• Most posterior under retinaculum

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• Grooves posterior process of talus• Sustentaculum tali• Crossed in foot by flexor digitorum longus to

which it gives two slips• Inserted base of distal phalanx

Flexor Hallucis Longus MOB TCD

• Tibial nerve• Plantar flexes ankle• Flexes big toe• Supports medial longitudinal arch• Take off muscle

Flexor Hallucis Longus MOB TCD

Tibialis Posterior

• Deepest• Posterior surface of tibia • Below soleal line• Lateral to vertical line• Interosseous membrane• Arises from posterior surface of

fibula • Anterior to medial crest

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• Crossed by flexor digitorum longus in calf• Posterior to medial malleolus

grooves bone, type II collagen, tends to have poor blood supply

• Most anterior under the flexor retinaculum

• Inserted into tuberosity of navicular• All bones of the tarsus except talus • Base of middle three metatarsals

Tibialis Posterior MOB TCD

• Plantar flexor ankle• Invertor of foot• Supports medial arch• Avascular area behind

medial malleolus • Tibial nerve

Tibialis Posterior MOB TCD

Posterior Tibial Artery

• Branch popliteal artery

• Lower border of popliteus

• Under fibrous arch of soleus

• Between flexor digitorum longus and flexor hallucis longus

• Vena commitans

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• In the calf gives off • Nutrient artery to tibia• Peroneal artery• Nutrient artery to fibula• Perforating peroneal• Passes under flexor retinaculum• Gives off medial calcaneal artery which

pierces flexor retinaculum• Then ends under flexor retinaculum• Dividing into medial and lateral plantar

arteries

Posterior Tibial Artery MOB TCD

Tibial Nerve

• Leaves the popliteal fossa• Runs in middle of calf• Deep to soleus• Accompaning artery• Branches to soleus• Flexor digitorum longus and flexor hallucis

longus• Tibialis posterior

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Flexor Retinaculum

• Medial malleolus to calcaneus• Anterior to posterior• Tibialis posterior • Flexor digitorum longus• Posterior tibial artery• Medial calcaneal artery pierces retinaculum• Divides into medial and lateral plantar arteries • Tibial nerve• Gives off medial calcaneal nerve which accompanies artery• Divides into medial lateral plantar nerves• Flexor hallucis longus

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Causes of Compartment Syndromes

• May be acute or chronic• Sudden increase in exercise• Haematoma• Callus• Fracture

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Compartment Syndromes

• Mainly anterior compartment• Tibialis anterior main muscle

affected as only supplied by anterior tibial, other muscles also supplied by perforating peroneal

• Increasing pressure causes loss of sensation of first cleft due to pressure on deep peroneal nerve

• Fasciotomy

Or• Posterior or lateral compartments

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Posterior Compartment

• Posterior compartment• Posterior border of tibia• Posterior intermuscular septum

Divided• Superficial• Deep• Deep posterior

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• Superficial compartment• Posterior intermuscular septum• Posterior border of tibia

Posterior Compartment MOB TCD

Superficial Posterior Compartment

• Medial and lateral gastrocnemii• Plantaris• Soleus• Forming the achilles tendon• Tibial nerve

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Deep Posterior Compartment

• Popliteus• Flexor digitorum longus• Flexor hallucis longus• Deepest is tibialis posterior

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Chronic Exertional Compartment Syndrome (CECS)

• Significant morbidity/limitation activity to athletes• Activity related, reversible, myofascial

intracompartmental pressure increase• Results in decreased tissue perfusion and

neuromuscular function abnormalities• Predilection for the lower leg

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The fibular origin of FDL can partially (or sometimes almost completely) compartmentalize TP and acts to resist increases in intracompartmental volume and therefore cause increased pressure

The presence and extent of a fibular origin of FDL may act as an anatomical predisposition to the development of CECS

Chronic Exertional Compartment Syndrome (CECS)

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