Anterior & Lateral Leg Dorsum of Foot

Question 1

Properties of Anterior Leg Compartment

Answer 1

• dorsiflex foot, extend toes, inverter
• deep fibular nerve
• 4 muscles
• most prone to compartment syndrome as it is rigid on 3 sides

Question 2

Properties of Lateral Leg Compartment

Answer 2

• evert foot
• 2 muscles
• superficial fibular nerve
• smallest compartment
• pass posterior to lateral malleolus

Question 3

Tibialis Anterior

Answer 3

-most superficial and medial
-strongest dorsiflexor
O: lateral tibial condyle & shaft of tibia
I: medial 1st cuneiform & head of 1st metatarsal
A: dorsiflexes & inverts foot (with tibialis posterior)
N: Deep fibular nerve

Question 4

Extensor Digitorum Longus (EDL)

Answer 4

-most lateral
-4 tendons form superior to ankle, bound in sheath with tendon fo fibularis tertius
O: superior shaft of fibula & interosseous membrane
I: middle & distal phalanges of 2nd-5th toes
A: dorsiflexes foot, extends 2nd-5th toes
N: deep fibular nerve

Question 5

Fibularis Tertius

Answer 5

-continuum of EDL, separate tendons, common sheath
-occasionally absent
O: inferior shaft of fibula & interosseous membrane
I: base of 5th metatarsal
A: dorsiflexes foot, everts foot (both weakly)
N: deep fibular nerve

Question 6

Extensor Hallicus Longus (EHL)

Answer 6

-deep between tibialis anterior & EDL
O: middle shaft of fibula & interosseous membrane
I: base of distal phalanx of hallux
A: dorsiflexes foot, extends hallux
N: Deep fibular nerve

Question 7

Fibularis Longus

Answer 7

-longer, superficial
-tendon passes deep to tendon of fibularis brevis, crosses sole
O: lateral head & superior shaft of fibula
I: plantar surface of 1st cuneiform & base of 1st metatarsal
A: everts & weakly plantar flexes
N: superficial fibular nerve

Question 8

Fibularis Brevis

Answer 8

-deep to fibularis longus
-tendon passes superficial to FL tendon (w/o crossing at sole)
O: lateral inferior shaft of fibula
I: lateral base of 5th metatarsal (merges with FT)
A: Everts and weakly plantar flexes
N: superficial peroneal nerver

Question 9

Common Fibular Nerve

Answer 9

• division of sciatic nerve
• leaves lateral popliteal fossa
• superficial to lateral head of gastrocnemius
• subject to compression by fibular head
• causes “foot drop”
• divides into superficial & deep fibular nerve
• superficial: lateral compartment
• deep: anterior compartment, dorsal foot muscles

Question 10

Deep Fibular Nerve

Answer 10

• anterior compartment
• enters between fibularis longus & fibular neck
• descends with anterior tibial artery, lateral to tibialis anterior
• crosses ankle into dorsum of foot
• between EHL & EDL

Question 11

Superficial Fibular Nerve

Answer 11

• lateral compartment
• enters between fibular longus & fibular neck
• descends deep to fibularis longus
• no motor branches continue to foot

Question 12

Anterior Tibial Artery

Answer 12

• arises from division of popliteal artery in posterior compartment
• pierces superior interosseous membrane to enter anterior compartment
• joins & descends with deep fibular nerve
• becomes DP at inferior extensor retinaculum

Question 13

Dorsalis Pedis Artery

Answer 13

• palpable between tendons of EHL & EDL

- dorsalis pedis & posterior tibial pedal pulses

Question 14

Properties of Dorsum of Foot

Answer 14

• 5th muscle compartment
• deep to dorsal fascia, superficial to dorsal interosseous fascia
• deep fibular nerve
• dorsalis pedis artery
• tendons of EHL, EDL

Question 15

Extensor Halliucis Brevis & Extensor Digitorum Brevis

Answer 15

-deep tendons of EHL and EDL
O: lateral calcaneus
I: tendons of EDL to 2nd-4th toes (EDB), base of proximal phalanx of hallux (EHB)
A: extend 1st-4th toes, assist tendons of long extensors in toe extension
N: Deep Fibular nerve

Question 16

Deep Plantar Arch

Answer 16

• anastomotic network in sole
• Dorsalis pedis: deep plantar branch
• Posterior Tibial: deep branch of lateral plantar
• ensures perfusion to foot

Question 17

Cutaneous Innervation of Anterior Lower Limb

Answer 17

-lumbar & sacral plexuses
-anterior predominantly lumbar levels
-significant overlap between adjacent dermatomes
-Lateral cutaneous nerve of thigh (L2,L3)
Femoral Nerve (L2-L4)
-saphenous nerve from femoral
-sural nerve (from tibia and common fibular)

Question 18

Cutaneous Innervation of Dorsum of Foot

Answer 18

• lumbar & sacral plexus
• foot predominantly sacral
• saphenous nerve (from femoral)- medial foot
• superficial & deep fibular nerves - dorsum
• deep fibular only 1st and 2nd webspace
• sural nerve - lateral foot

Question 19

Shin Splints

Answer 19

• microtears of tibialis anterior at attachments to tibia &/or crural fascia
• pain between tibia & fibular
• edema distal 2/3 anterior leg
• minor form of compartment syndrome
• unconditioned exercise
• insufficient warmup

Question 20

Foot Drop

Answer 20

• injury to common fibular nerve (typically via compression)
• superficial course around fibular nerve: stirrups without adequate padding, bedrails
• weakness/paralysis of anterior/lateral compartments
• loss of dorsiflexion (unopposed plantar flexion)
• limb length discrepancy
• compensatory gaits
• dorsal foot numbness

Question 21

Compartment Syndrome

Answer 21

• sequela of trauma
• any muscle compartment due to fx, vascular injury/reperfusion
• muscle compartment pressure exceeds perfusion pressure
• muscle & nerve ischemia leading to muscle necrosis, paralysis, paresthesia
• Fasciotomy to decompress compartment to create room to allow for expansion

Question 22

Leg Fasciotomy

Answer 22

• injury to intervention must be less than 6 hours
• two incisions
• release 4 comaprtments
• incise fascia from knee to ankle
• deep posterior compartment most difficult with highest morbidity
• follow with reductioin/fixation &/or vascular repair

Question 23

Dorsalis Pedis Pulse

Answer 23

• subcutaneous distal to extensor retinaculum
• lateral to EHL tendon
• smaller/weaker than PT
• absence may indicate PVD
• acute loss may indicate acute arterial occlusion

Question 24

5 P’s of Arterial Insufficiecny

Answer 24

Pain
Pallor
Paresthesia
Paralysis
Pulselessness