Anatomy Content Block 3 - 7

Front 1

The Lumbar Plexus

Back 1

- arises from the 1st four lumbar spin nerves: L1-L4
- located within the psoas major muscle
- some of its minor branches innervate the abdominal wall, but its main branches descend to innervate the anterior thigh, via the femoral and obturator nerves

Front 2

The Sacral Plexus

Back 2

- originates from spinal nerves L4-S4 and is found directly behind the lumbar plexus
- about ½ of the branches of the sacral plexus serve the buttocks and lower limb but the most important branch for the lower limb is the 'sciatic' nerve, which divides into the tibial nerve and common fibular nerves

Front 3

Innervation of Muscle Compartments of Thigh

Back 3

Front 4

Innervation of Lower Limb Diagram

Back 4

Front 5

Bones of the Foot

Back 5

Front 6

Muscles of the Posterior Compartment of the Leg

Back 6

Superficial:
- gastrocnemius
- plantaris
- soleus
Deep:
- popliteus
- FDL - flexor digitorum longus
-FHL - flexor hallicus longus
- tibialis posterior

Cross knew and flex leg = gastrocnemius, plantar is, popliteus
Invert foot = FDL, FHL, tibialis posterior

Front 7

Gastrocnemius

Back 7

Superficial
O: via 2 heads from the medial and lateral condyles of the femur
In: posterior calcareous bone, via the calcaneal tendon
A: plantar flexes foot when knee is extended, but can also flex the knee since it crosses the knee joint
I: tibial nerve

Front 8

Soleus

Back 8

Superficial
O: an extensive origin from superior tibia, fibula and interosseus membrane
In: posterior calcareous bone, via the calcaneal tendon
A: plantar flexes foot, impotent postural and locomoto muscle during running and walking
I: tibial nerve

Front 9

Plantaris

Back 9

Superficial
O: posterior femur above the lateral condyle
In: via a long, thin tendon into the calcareous bone
A: assists in knee flexion and plants flexion of foot
I: tibial nerve

Front 10

Flexor Digitorum longus (FDL)

Back 10

Deep:
O: extensive origin on the posterior tibia
In: tendon runs behind medial malleolus and splits into distal phalanges of toes 2-5
A: plantar flexes and inverts foot, flexes the toes, helps the foot 'grip' the ground
I: tibial nerve

Front 11

Flexor Hallucis Longus

Back 11

Deep
O: middle part of the shaft of fibula, interosseous membrane
In: tendon runs under foot to the distal phalanx of big toe
A: plantar flexes and inverts foot, flexes the big toe at all joints, serves as a push off muscle during walking
I: tibial nerve

Front 12

Popliteus

Back 12

Deep
O: lateral condyle of the femur and lateral meniscus of the knee
In: proximal tibia
A: flexes and rotate leg medially to 'unlock' the knee from full extension when flexion begins
I: tibial nerve

Front 13

Tibialis Posterior

Back 13

Deep
O: superior tibia and fibula and also interosseous membrane
In: tendon passes behind medial malleolus and under arch of foot to insert into several tarsals and metatarsals 2-4
A: prime mover of foot inversion, plantar flexes the foot
I: tibial nerve

Front 14

3 tendons of the 3 posterior compartment flexor muscles along the medial side of the food

Back 14

"Tom, Dick and Harry"
- post. tibial, flex hall longs, flex, digit longus

Front 15

Muscles of the Lateral Compartment of the Leg

Back 15

1. peroneus longus (fibularis longus) *
2. peroneus brevis (fibularis brevis) *

*plantar flexion and eversion of foot

Front 16

Peroneus Longus

Back 16

O: head and upper portion of the lateral side of the fibula
In: by a long tendon that curves under the foot t othe first metatarsal and medial cuneiform
A: plantar flexes and everts the foot
I: superficial fibular nerve

Front 17

Peroneus Brevis

Back 17

O: distal shaft of fibula
In: via a tendon running behind lateral malleolus to insert on proximal end of 5th metatarsal
A: plantar flexes and everts foot
I: superficial fibular nerve

Front 18

Muscles of the Anterior Compartment of the Leg

Back 18

1. Tibialis Anterior (TA)
2. Extensor Digitorum Longus (EDL)
3. Extensor Hallicus Longus (EHL)

* all dorsiflex the foot at the ankle

Front 19

Tibialis Anterior

Back 19

Superficial
O: lateral condyle and upper 2/3 of tibial shaft, interosseous membrane
In: via a tendon into the medial cuneiform and first metatarsal
A: prime mover of foot dorsiflexion, inverts the foot
I: deep fibular nerve

Front 20

Extensor Digitorum Longus

Back 20

Deep
O: lateral condyle of the tibia, proximal 1/3 of fibula and interosseous membrane
In: middle and distal phalanged of toes 2-5
A: prime mover of toe extension and dorsiflexes the foot
I: deep fibular nerve

Front 21

Extensor Hallucis Longus

Back 21

Deep
O: shaft of the fibula and interosseous membrane
In: tendon inserts into distal phalanx of the big toe
A: extends the big toe, dorsiflexes the foot
I: deep fibular nerve