Anatomy of the Anterior compartment of leg and Dorsum of the foot

1. Anterior Compartment of the Leg
&
Dorsum of the Foot
Dr Rajiv Ranjan
RIMS, Ranchi
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2. Crural fascia &
cutaneous innervation
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3. pes anserinus
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4. D
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5. Compartments
of Leg
3 compartments
1. Anterior(extensor)
2. Lateral(fibular)
3. Posterior(flexor)
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6. Anterior Fascial Compartment
Contents of the Anterior Fascial Compartment of the Leg
• Muscles: tibialis anterior, extensor hallucis longus, extensor
digitorum longus, peroneus tertius
• Blood supply: Anterior tibial artery (mainly)
• Nerve supply: Deep peroneal nerve (L4,L5)
Primarily responsible for dorsiflexion of foot & ankle (acting
from above); pull the body forwards on the fixed foot during
walking (acting from below).
Anterior tibial artery & deep peroneal nerve run deeply just
anterior to the interosseous membrane
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7. Muscles
Overview
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8. Tibialis Anterior
• O –
lateral condyle and proximal 2/3rd
of lateral surface of the tibial shaft
adjoining interosseous membrane
• I – Medial and inferior surfaces of
Medial cuneiform and base of first
metatarsal bone
• V – Ant. tibial A
• N – Deep fibular N
• A – Dorsiflexor of the ankle and
Invertor of the foot
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9. Extensor hallucis longus
• O –
Middle ½ of the medial surface of
the fibula &
adjacent interosseous membrane
• I – dorsum of the base of distal
phalanx of great toe
• V – Ant. tibial A & fibular A
• N – Deep fibular N
• A –
• dorsiflexion of foot at ankle
• Dorsiflex (extends) hallux (L5)
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10. Extensor digitorum longus
• O –
lateral condyle of the tibia
 proximal ¾th of the medial
surface of the fibula
adjacent interosseous membrane
• I – Extensor expansion of lateral
four toes
• V – Ant. tibial A & fibular A
• N – Deep fibular N
• A –
• Dorsiflexon at the ankle joint
• extends the lateral four toes
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11. Fibularis Tertius
• O –
Distal 3rd of the medial surface
of the fibula &
Adjacent interosseous
membrane
• I – dorsum of the base of fifth
metatarsal bone
• V – Ant. tibial A
• N – Deep fibular N
• A –
• Dorsiflexion @ ankle
• eversion of the foot
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12. Extensor Retinacula
 Band-shaped thickenings of deep
fascia
 prevent bowstringing underlying
tendons
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13. Sup. Extensor Retinacula
 Band like
 Attachments –
 laterally to the of anterior
border of the fibula
 medially to the anterior border
of the tibia
 Str. passing deep
 Tendons of Tibialis Anterior, Extensor Hallucis
Longus, Extensor Digitorum Longus &
Fibularis Tertius
 Anterior Tibial Vessels & Deep Fibular Nerve
Str. Passing superficial
 Superficial fibular nerve
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14. Superior
Extensor
Retinacula
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15. Inferior Extensor Retinacula
 Y-shaped band
 Stem is attached to the upper surface of the
calcaneus
 Passes medially enclosing tendons of fibularis
tertius and extensor digitorum longus
 Proximal limb
 Deep layer passes deep to the tendons of EHL
& TA , but superficial to the anterior tibial
vessels & deep fibular N
 Superficial layer crosses superficial to the
tendons of EHL & TA
 Both adhere and attach to medial malleolus
 Distal limb
 Extends downwards and medially to blend
with the plantar aponeurosis
 Superficial to the tendons of EHL & TA
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16. Inferior
Extensor
Retinacula
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17. Anterior Tibial Artery
 Smaller terminal branch of the popliteal artery
 Arises at the lower border of popliteus
 accompanying anterior tibial veins run as venae
comitantes
 Passes forward into ant. Compartment of leg through
an opening in the upper part of the interosseous
membrane at the neck of fibula
 Descends on the anterior surface of the interosseous
membrane, accompanied by the deep peroneal nerve
 In front of the ankle joint, the artery becomes the
dorsalis pedis artery
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18. Branches
• Posterior and anterior tibial recurrent A
• Muscular As
• Perforating A
• Anterior medial malleolar artery
• Anterior lateral malleolar artery
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19. Anterior Tibial A Dorsalis pedis A
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20. Deep fibular Nerve
 one of the terminal branches of the common peroneal N
 Arises in the substance of the peroneus longus muscle on
the lateral side of the neck of the fibula
 Enters the anterior compartment by piercing the anterior
fascial septum
 Descends deep to the extensor digitorum longus muscle
 Lies between extensor digitorum longus and tibialis
anterior & then the latter and extensor hallucis longus
 The nerve descends first lying lateral, then anterior, and
finally lateral to the anterior tibial artery [nervi hesitans]
 Branches – 1. Muscular branches 2. Articular branch
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22. [nervi hesitans]
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23. Applied
risk for compartment syndrome
near the ankle, tendons of TA, EHL & EDL are close to
tibia & may be injured by open # or by callus formation
during # healing
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24. Dissection
Overview
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25. Dorsum of the foot
Cutaneous Innervation
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26. Dorsum of the
foot
Dorsal venous Arch
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27. Extensor hallucis brevis
• O –
• Dorsal surface of calcaneus &
• Deeper aspect of stem of
inferior extensor retinaculuIm
• I – Base of proximal phalanx of
hallux
• V – Dorsalis Pedis A
• N – Deep fibular N
• A – extend the 1st toe at the
metatarsophalangeal joint
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28. Extensor Digitorum
Brevis
• O –
• Dorsal surface of calcaneus &
• Deeper aspect of stem of inferior
extensor retinaculuIm
• I – 3 tendons attach to the lateral
sides of the tendons of extensor
digitorum longus
• V – Dorsalis Pedis A
• N – Deep fibular N
• A – Extend the medial 3 toes at the
metatarsophalangeal joint
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29. Dorsalis Pedis Artery
 Continuation of anterior tibial artery
 Course :
 It lies between the tendon of extensor hallucis
longus medially and the digital branch of the
deep fibular N laterally
 then it is crossed by the tendon of extensor
hallucis brevis
 runs to the base of the first intermetatarsal
space and passes down into the sole between the
heads of the first dorsal interosseous, to join the
lateral plantar artery & complete the plantar
arch.
 Its pulsation can be palpated lateral to
the extensor hallucis longus tendon on a
line from the midpoint between the two
malleoli towards the first toe cleft
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30. Dorsalis Pedis Artery
Branches
 Tarsal arteries : lateral and medial
 Arcuate artery : gives 2nd to 4th dorsal
metatarsal arteries which bifurcates
 First dorsal metatarsal artery
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31. Extensor Expansion
Same as EE of Hand
triangular aponeurotic sheaths, with a hood-like
appearance
Divide into a central slip & two lateral slips over
the proximal phalanx
function as the compound tendinous
attachment of the:
 Extensor digitorum longus
 Lumbrical
 Plantar interossei and dorsal interossei
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