Leg Muscles, Vasculature and Innervation

Question 1

Tibialis Anterior

Answer 1

most medial and superficial dorsiflexor
lies against lateral surface of tibia
tendon has its own synovial sheath
strongest dorsi flexor
O- Lateral condyle and superior 1/2 of lateral surface of tibia and interosseous membrane
I- Medial and inferior surfaces of medial cuneiform and base of 1st metatarsal
A- Dorsiflexion and inversion
N- Deep fibular (peroneal) nerve (L4,L5)
B- Anterior Tibial Artery

Question 2

Extensor Digitorum Longus

Answer 2

most lateral of anterior leg muscles
forms 4 tendons that attach to phalanges
has a common synovial sheath with FT, each tendon form the extensor expansion over proximal phalanx of toe
O- Lateral condyle of tibia and superior 3/4 of medial surface of fibula and interosseous membrane
I- Middle and distal phalanges of lateral 4 digits
A - Extension of lateral 4 digits and dorsiflexion
N- Deep fibular nerve (L4,L5)
B- Anterior tibial artery

Question 3

Fibularis Tertius

Answer 3

separated part of FDL
not always present
O- Inferior 1/3 of anterior surface of fibula and interosseous membrane
I- Middle and distal phalanges of lateral 4 digits
A- Extension of lateral 4 digits and dorsiflexion
N- Deep fibular nerve (L4,L5)
B- Anterior Tibial Artery

Question 4

Extensor Hallicus Longus

Answer 4

thin muscle, lies deep b/w TA and EDL at its superior attachment
rises to surface in distal 1/3 of leg
deep fibular nerve and anterior tibial artery found b/w EHL and TA
O- Middle part of anterior surface of fibula and interosseous membrane
I- Base of distal phalanx of great toe (hallux)
A- Extension of great toe and dorsiflexion
N- Deep fibular nerve (L4,L5)
B- Anterior tibial artery

Question 5

Fibularis Longus

Answer 5

longer and more superficial of the two
tendon can be observed proximal and posterior to lateral malleoulus
tendon passes inferior to fibular trochlea
O- Head and superior 2/3 lateral surface of fibulaI
I- Base of 1st metatarsal and medial cuneiform
A- Eversion and weak plantarflexion
N- Superficial fibular nerve (L5,S1,S2)
B- Perforating branches of fibular an anterior tibial arteries

Question 6

Fibularis Brevis

Answer 6

lies deep and is shorter than FL
tendon can be palpated inferior to lateral malleolus
O- Inferior 2/3 of lateral surface of fibula
I- Tuberosity of base of 5th metatarsal
A- Eversion and weak plantarflexion
N- Superficial fibular nerve (L5,S1,S2)
B- Perforating branches of fibular and anterior tibial arteries

Question 7

Gastrocnemius

Answer 7

most superficial muscle, two headed two joint muscle
O- Lateral head- popliteal surface, lateral aspect of lateral condyle of femur
Medial head- popliteal surface of femur superior to medial condyle
I- Posterior surface of calcaneus via calcaneal tendon
A- Plantarflexion with extended knee; leg flexion
N- Tibial Nerve (S1,S2)
B- Popliteal artery

Question 8

Soleus

Answer 8

deep to gastrocnemeus
workhorse of plantar flexion
tendinous arch of soles, continuos proximal attachment, shaped like an inverted U
accessory soleus present 3% of the time, lies medial to calcaneus tendon
O- Posterior aspect of head and superior 1/4 of posterior surface of fibula; soleal line, middle 1/3 of medial border of tibia
I- Posterior surface of calcaneus via calcaneal tendon
A- Plantarflexion indépendant of position of knee
N- Tibial nerve (S1,S2)
B- Posterior tibial arteries

Question 9

Plantaris

Answer 9

short belly, long tendon - often mistaken for a nerve, freshman’s nerve
absent 5-10%
O- Inferior end of lateral supracondylar line of femur; oblique popliteal ligament
I- Posterior surface of calcaneus via calcaneal tendon
A- Weak plantarflexion
N- Tibial Nerve (S1,S2)
B- Popliteal artery

Question 10

Popliteus

Answer 10

forms inferior part of floor of popliteal fossa
tendon emerges from joint capsule of knee
O- Lateral surface of lateral condyle of femur
I- Posterior surface of tibia, superior to soleal line
A- Weak flexion of leg; unlocks knee by rotating femur 5 degrees on flexed tibia; medially rotates tibia of unplanted limb
N- Tibial nerve (L4,L5,S1)
B- Popliteal artery

Question 11

Flexor Hollucis Longus

Answer 11

powerful flexor of all joints of great toe
tendon passes posterior to medial malleolus and inferior to the sustentaculum tali
then runs b/w two sesamoid bones in tendon of flexor hallucis brevis
O- Inferior 2/3 of posterior surface of fibula; inferior part of interosseous membrane
I- Base of distal phalanx of great toe
A- Flexion of great toe at all joints; weak plantar flexion
N- Tibial nerve (S2,S3)
B- Fibular artery

Question 12

Flexor Digitorum Longus

Answer 12

tendon crosses over TP superior to medial malleolus
tendon passes posterior to medial malleolus
then passes superficial to tendon of FHL in sole of foot
direction of pull realigned by quadrates planate muscle
O- Medial part of posterior surface of tibia inferior to soleal line
I- Base of distal phalanges of lateral 4 digits
A- Flexion of lateral 4 digits; plantarflexion
N- Tibial Nerve (S2,S3)
B- Posterior tibial artery

Question 13

Tibialis Posterior

Answer 13

deepest muscle in posterior compartment
b/w FHL and FDL
tendon passes immediately posterior to medial malleolus
O- Interosseous membrane; posterior surface tibia inferior to soleal line; posterior surface fibula
I- Tuberosity of navicular, cuneiform, cuboid, sustentaculum tali and bases of 2nd-4th metatarsals
A- Plantarflexion and inversion
N- Tibial Nerve (L4,L5)
B- Posterior Tibial Artery