A&P 1.15

Question 1

Compartments of the Leg

How many layers are within the posterior compartment?

Answer 1

3

Question 2

Compartments of the Leg

Name the layers of the posterior comparmtent of the leg and the muscles they contain

Answer 2

Deep:
- Tibialis posterior
- Flexor hallucis longus
- Flexor digitorum longus
- Popliteus

Intermediate:
- Plantaris
- Soleus

Superficial:
- Gastrocnemius

Question 3

Compartments of the Leg

What is the arrangement of tendons that run posterior to the medial malleolus?

What “pneumonic device” is used to remember this?

Answer 3

Tibialis posterior
Flexor digitorum longus
Flexor hallucis longus

Tom, Dick, & Harry P

Question 4

Deep Posterior Leg Compartment - LOIA

Tibialis Posterior

Answer 4

L: Posterior leg deep
O: Interosseous membrane, tibia and fibular
I: 8 TENDONS (navicular, all 3 cuneiforms, cuboid, base of 2nd, 3rd, and 4th metatarsals
A: Plantarflexion, inversion of foot at ankle

Question 5

Deep Posterior Leg Compartment - LOIA

Flexor hallicus longus

Answer 5

L: Posterior leg deep
O: Distal 2/3 of fibula and interosseous membrane
I: Base of distal phalanx of hallux
A: Flexion of hallux, plantarflecion of foot at ankle

Question 6

Deep Posterior Leg Compartment - LOIA

Flexor digitorum longus

Answer 6

L: Posterior leg deep
O: Tibia
I: Base of distal phalanges of lateral 4 toes
A: Flexion of lateral 4 toes, plantarflexion of foot at ankle

Question 7

Deep Posterior Leg Compartment - LOIA

Popliteus

Answer 7

L: Posterior leg deep
O: Lateral epicondyle of femur
I: Proximal, medial tibia
A: Weak flexion of knee, unlocks knee from extended position

Question 8

Intermediate Posterior Leg Compartment - LOIA

Soleus

Answer 8

L: Posterior leg intermediate
O: Head of fibula, fibula, soleal line, posterior surface of tibia

I: Calcaneus via calcaneal tendon
A: Plantarflexion of foot at ankle

• AKA “2nd heart” due to amt of blood in the leg; when it contracts, it helps to return blood to heart (veinous return)
• Contributes to bulk of calf ms.
• Parallel fiber direction

Question 9

Markings of Posterior Leg

Soleal line

Answer 9

Oblique line running on posterior proximal tibia
- attachment point for soleus muscle

Question 10

Intermediate Posterior Leg Compartment - LOIA

Plantaris

Answer 10

L: Posterior leg intermediate
O: Lateral supracondylar line of femur
I: Medial surface of calcaneal tendon (achilles tendon)
A: Weakly assists gastrocnemius in plantarflexion of foot & flexion of leg at knee

Runs medially through condyles of femur down medial side of leg/soleus

• AKA “Freshmans nerve” for 1st yr med students who mistake this for a nerve
• More tendon than it is muscle belly
• Parallel fiber direction

Question 11

Muscle Insertions of Posterior Leg

Calcaneal tendon

Answer 11

A combination of tendon insertions for:
* soleus
* plantaris
* gastrocnemius muscles

AKA Achilles tendon

• Largest tendon in the body
• Very easy to injure

Question 12

Superficial Posterior Leg Compartment - LOIA

Gastrocnemius

Answer 12

L: Posterior leg superficial
O:
- Lateral head: lateral condyle of femur
- Medial head: medial condyle of femur
I: Calcaneus via calcaneal tendon
A: Plantarflexion of foot at ankle, flexion of leg at knee

Question 13

Sciatic Nerve***

Answer 13

• Begins at L4-S3 spinal nerves
• Runs through greater sciatic notch
• Passes inferiorly between ischial and gluteal tuberosities, over deep 6 lateral rotators [over, under or bisecting (running through) piriformis]
• Branches at popliteal region into common tibial nerve and fibular nerve
• Tibial branch of sciatic nerve runs through tarsal tunnel w/ tibialis posterior, flexor digitorum longus, flexor hallicus longus (Tom, Dick & Harry)
• True sciatica is inflammation of sciatic nerve
• Can be compressed by piriformis
• Often used as a “catch all” for low back pain
• Largest nerve in the body