L17: Musculo-neuro-vascular systems of the anterior and posterior compartments of the leg and popliteal fossa

Question 1

popliteal fossa

Answer 1

diamond shaped region at back of knee

Question 2

popliteal fossa - boundaries

Answer 2

• semimembranosus
• biceps femoris (long head)
• gastrocnemius (medial and lateral head)

Question 3

popliteal fossa - floor + roof

Answer 3

floor:
- popliteal surface of femur
- oblique popliteal ligament
- popliteus and popliteal fascia

roof:
- skin and fasciae lata

Question 4

popliteal fossa - contents

Answer 4

Superficial:
- small saphenous vein - drains the lateral superficial leg and joints the popliteal vein
Intermediate:
- tibial nerve
- common fibular [peroneal] nerve
Deep:
-popliteal artery
- popliteal vein
Fat
Lymphatic tissue

Question 5

fascia of the leg

Answer 5

leg muscles and bones are covered by crural fascia
- it is continuous superiorly with fascia lata of thigh
- attached around knee to patellar ligament, tibial tuberosity, tibial condyles and head of fibula
- anteriorly blends with periosteum covering shin (tibia)

Question 6

three compartments of leg

Answer 6

• anterior compartment
• lateral compartment
• posterior compartment
  
  • superficial
  • deep

Question 7

the leg is divided into 3 compartments by :

Answer 7

• anterior intramuscular septa
• posterior intramuscular septa
• interosseous membrane

Question 8

compartment syndrome

Answer 8

• excessive swelling or bleeding within a compartment
• usually after an injury
• exerts pressure on anything within that compartment: nerves, muscles, arteries, and veins
• can cause irreversible damage to all tissues in compartment
• treated with emergency fasciotomy

Question 9

anterior compartment muscles 4

Answer 9

1. tibialis anterior
2. extensor digitorum longus
3. extensor hallucis longus
4. fibularis [peroneus] tertius

Question 10

anterior compartment muscles
action

Answer 10

• dorsiflexion of foot
• extension of toes

Question 11

anterior compartment innervation

Answer 11

deep fibular nerve - is a branch of common fibular [peroneal] nerve

Question 12

extensor retinacula of anterior compartment

Answer 12

these are thickened bands of crural fascia

superior extensor retinaculum: passes between distal tibia and fibula

inferior extensor retinaculum: y-shaped retinaculum, attached to: calcaneus and medial malleolus + planter aponeurosis

Question 13

tibialis anterior; origin

Answer 13

tendon of tibialis anterior is prominent on dorsum of foot close to ankle

origin:
-lateral tibial condyle
-antero-supero-lateral surface of tibia
-interosseous membrane

Question 14

tibialis anterior ; insertion

Answer 14

-medial and inferior surface of medial cuneiform
-base of 1st metatarsal

Question 15

tibialis anterior; innervation + action

Answer 15

innervation: deep fibular nerve

actions: dorsiflexes ankle joint + inverts foot at subtalar joint

Question 16

extensor digitorum longus; origin

Answer 16

• lateral tibial condyle
• superior 3/4 of anterior fibular and adjacent interosseous membrane

Question 17

extensor digitorum longus; insertion

Answer 17

• divides into 4 slips
• slips insert into middle and distal phalanges via extensor expansions (digit 2-5)

Question 18

extensor digitorum longus; innervation + actions

Answer 18

innervation: deep fibular nerve

actions: extends digits 2-5, dorsiflexes ankle

Question 19

extensor expansions

Answer 19

• triangular shaped expansions
• over metatarsal phalangeal [MTP] joints
• extensor digitorum longus [EDL], foot lumbricals and foot interossei insert into extensor expansions

Question 20

extensor hallucis longus; origin

Answer 20

• middle 1/2 of anterior fibula
• adjacent interosseous membrane

Question 21

extensor hallucis longus; insertion

Answer 21

dorsal aspect if base of distal phalanx of digit 1 [big toe]

Question 22

extensor hallucis longus; innervation + action

Answer 22

innervation; deep fibular nerve

actions: extends digit 1 + dorsiflexes ankle

Question 23

fibularis tertius; origin

Answer 23

aka peroneus tertius

origin:
- inferior 1/3 of anterior fibula
- adjacent interosseous membrane

Question 24

fibularis tertius; insertion

Answer 24

dorsal surface of base of 5th metatarsal

Question 25

fibularis tertius; innervation + actions

Answer 25

innervation: deep fibular nerve

actions: dorsiflexes ankle + aids with foot eversion

Question 26

posterior compartment - superficial muscles 3

Answer 26

1. gastrocnemius
2. soleus
3. plantaris

Question 27

posterior compartment - superficial muscles - innervation + actions

Answer 27

• all innervated by tibial nerve, a branch of popliteal nerve
• all insert into achilles tendon
  -all plantarflex ankle
• triceps sura: gastrocnemius and soleus

Question 28

gastrocnemius; orgin

Answer 28

most superficial muscle in the posterior leg, it has 2 muscle bellies which unite at their tendon

origin:
-lateral head - lateral condyle of femur
-medial head - popliteal surface if femur, above medial condyle

Question 29

gastrocnemius; insertion

Answer 29

calcaneus via achilles tendon

Question 30

gastrocnemius; innervation + actions

Answer 30

innervation: tibial nerve
actions: plantar flexes ankle, raises heel during walking, flexes knee

Question 31

soleus; origin

Answer 31

lies deep to gastrocnemius

origin:
- fibular: posterior head and proximal 1/4 of posterior fibula
- soleal line and middle 1/3 of medial border of tibia

Question 32

soleus; insertion

Answer 32

calcaneus via achilles tendon

Question 33

soleus; innervation + actions

Answer 33

innervation: tibial nerve
actions: plantar flexes ankle independent of knee position + stabilises leg on foot

Question 34

plantaris; origin

Answer 34

lies between gastrocnemius and soleus, vestigial muscle- absent in 5-10% of people

origin;
- lateral supracondylar line of femur
- oblique popliteal ligament

Question 35

plantaris; insertion

Answer 35

calcaneus via achilles tendon

Question 36

plantaris; innervation + actions

Answer 36

innervation: tibial nerve
actions: weakly assists with plantar flexion of ankle and flexion of knee

Question 37

flexor retinaculum of posterior compartment

Answer 37

• runs from medial malleolus to calcaneus
• encloses the tarsal tunnel, a space between flexor retinaculum and bones underneath it
• permits passage of plantar flexor tendons, nerves and vessels to sole of foot

Question 38

muscles of deep posterior compartment 4

Answer 38

1. popliteus
2. tibial posterior
3. flexor digitorum
4. flexor hallucis longus

all innervated by tibial nerve, a branch of the popliteal nerve

Question 39

Tom, Dick And Very Nervous Harry (from medial to lateral)

Answer 39

Tibialis posterior
flexor Digitorum longus
tibial Artery
tibial Vein
flexor Hallucis longus

Question 40

popliteus; origin

Answer 40

lateral femoral condyle and lateral meniscus

Question 41

popliteus; insertion

Answer 41

posterior tibial surface, superior to soleal line

Question 42

popliteus; innervation + actions

Answer 42

innervation: tibial nerve
actions: weakly flexes knee, ‘‘unlocks’’ a fully extended knee to permit flexion, contraction externally rotates femur by ~5* on tibial plateau to permit flexion

Question 43

tibialis posterior; origin

Answer 43

-Posterior tibia, inferior to soleal line
-Posterior fibula
- Adjacent interosseous membrane

Question 44

tibialis posterior; insertion

Answer 44

-Inferior surface of navicular
-Cuneiforms
-Cuboid
-Sustentaculum tali of calcaneus
-Bases of metatarsals 2-4

Question 45

tibialis posterior; innervation + actions

Answer 45

innervation: tibial nerve
actions: inverts foot

Question 46

flexor digitorum longus; origin

Answer 46

medial part of posterior tibial surface, inferior to soleal line

Question 47

flexor digitorum longus; insertion

Answer 47

base of distal phalanges 2-5

Question 48

flexor digitorum longus; innervation + actions

Answer 48

innervation: tibial nerve
actions: flexes digits 2-5, plantarflexes ankle, supports longitudinal arches of foot

Question 49

flexor hallucis longus; origin

Answer 49

-inferior 2/3 of posterior fibula
-adjacent interosseous membrane

Question 50

flexor hallucis longus; insertion

Answer 50

base of distal phalanx of great toe [hallux]

Question 51

flexor hallucis longus; innervation + action

Answer 51

innervation: tibial nerve
actions: flexes digit 1 at all joints, weakly plantarflexes ankle, supports medial longitudinal arch of foot

Question 52

surface anatomy of posterior leg

Answer 52

popliteal fossa, gastrocnemius muscle [medial and lateral heads], soleus muscle, calcaneal [achilles] tendon, medial malleolus of tibia, lateral malleolus of fibula, calcaneus

Question 53

popliteal artery divided into:

Answer 53

anterior and posterior tibial arteries

Question 54

arterial supply to the anterior leg

Answer 54

anterior tibial artery supplies anterior compartment of leg
- it reaches anterior compartment by passing through a gap in the superior interosseus membrane
- it descends between tibialis anterior and extensor hallucis longus
- descends deep to extensor retincula
- after passing inferior extensor retinaculum, becomes known as dorsalis pedis artery

Question 55

arterial supply to the posterior leg, 2

Answer 55

1. posterior tibial
   - passes through posterior compartment of leg and through tarsal tunnel
   - distal to tarsal tunnel it divides into medial and lateral plantar arteries
   - supplies posterior and lateral compartments of leg
2. fibular artery
   - descends in posterior compartment
   - supplies posterior compartment, perforating branches also supply lateral compartment

Question 56

arterial pulses of lower limb

Answer 56

proximal to distal:
- femoral artery
- popliteal artery
- posterior tibial artery
- dorsalis pedis

Question 57

venous drainage of the superficial leg

Answer 57

medial: great saphenous system, drains into femoral vein
lateral: small saphenous system, drains into popliteal vein

Question 58

venous drainage of the deep leg

Answer 58

anterior tibial vein: accompanies anterior tibial artery, drains anterior compartment, drains into popliteal vein

posterior tibial vein: accompanies posterior tibial artery, drains posterior compartment, drains into popliteal vein

fibular vein: accompanies fibular artery, drains into popliteal vein

Question 59

varicose veins

Answer 59

failure of valves in superficial venous systems
-great saphenous area
-small saphenous area

blood collects in superficial veins
can cause:
- pain, itching, swelling, bleeding can occur

Question 60

sensory innervation of leg

Answer 60

• saphenous nerve - branch of femoral nerve
• lateral sural cutaneous nerve - branch of fibular nerve
• medial sural cutaneous nerve - branch of tibial nerve