Lecture 3.5 - Popliteal Fossa and Leg

Question 1

What is the popliteal fossa and its boundaries?

Answer 1

• diamond-shaped space posterior to the knee
  boundaries:
• suprior lateral: biceps femoris
• superior medial: semimembranosus, semitendinosus
• inferior: medial/lateral heads of the gastrocnemius

Question 2

What blood vessels and nerves does the popliteal fossa contain?

Answer 2

• popliteal artery/vein
• tibial nerve
• common fibular nerve
• small saphenous vein

Question 3

What bones are in the leg (crus)? What are its muscle groups?

Answer 3

Bones:
- tibia (supports body weight)
- fibula (stability to ankle joint)
Muscles:
- anterior muscles (4)
- lateral muscles (2)
- posterior muscles (7)

Question 4

What kind of fascia is in the leg?

Answer 4

• deep fascia = crural fascia
• continuous with fascia lata of thigh
• crural fascia separates leg into 4 regions

Question 5

What are the actions of the anterior leg muscles? Lateral leg muscles? Posterior leg muscles?

Answer 5

Anterior muscles:
- dorsiflexion (extension) of foot and/or toes
Lateral muscles:
- eversion and plantarflexion of foot
Posterior muscles:
- plantarflexion (flexion) of foot and/or toes
- inversion of foot

Question 6

Which muscles are the anterior crural compartment? What do they do? What is their innervation?

Answer 6

• tibialis anterior, extensor hallucis/digitorum longus, fibularis tertius
• they dorsiflex the foot and extend the toes
• supplied by deep fibular nerve

Question 7

Which muscles are the lateral crural compartment? What do they do? What is their innervation?

Answer 7

• fibularis longus/brevis
• they evert the foot
• supplied by the superficial fibular nerve

Question 8

Which muscles are the posterior crural compartment? What do they do? What is their innervation?

Answer 8

• superficial: triceps surae, plantaris
• deep: tibialis posterior, flexor digitorum longus, flexor hallucis longus
• they plantarflex the foot and flex the toes
• supplied by tibial nerve

Question 9

Tibialis Anterior (OINA)

Answer 9

O: lateral tibial condyle, lateral surface of tibia, and interosseous membrane
I: medial cuneiform and first metatarsal
N: deep fibular nerve
A: dorsiflexes and inverts foot

Question 10

What is Foot-Drop?

Answer 10

paralysis of tibialis anterior causes foot drip de to injury to common fibular nerve or its deep branch

Question 11

What are shin-splints?

Answer 11

painful swelling of anterior compartment muscles after vigorous or lengthy exercise

Question 12

Extensor Hallucis Longus (OINA)

Answer 12

O: middle anterior fibula and interosseous membrane
I: distal phalanx of hallux
N: deep fibular nerve
A: dorsiflex foot; extends hallux

Question 13

Extensor Digitorum Longus (OINA)

Answer 13

O: lateral tibial condyle, proximal 2/3rds of fibula and interosseous membrane
I: middle and distal phalanges of lateral 4 digits
N: deep fibular nerve
A: dorsiflexes and everts foot; extends lateral 4 digits

Question 14

Fibularis Tertius (OINA)

Answer 14

O: lower fibula and interosseous membrane
I: base of 5th metatarsal
N: deep fibular nerve
A: dorsiflexes and everts foot

Question 15

Fibularis Longus (OINA)

Answer 15

O: head and superior lateral fibula
I: 1st metatarsal and medial cineiform
N: superficial fibular nerve
A: plarflexes and everts foot

Question 16

Fibularis Brevis (OINA)

Answer 16

O: inferior lateral fibula
I: tuberosity of 5th metatarsal
N: superficial fibular nerve
A: plantarflexes and everts foot

Question 17

How can the 5th metatarsal be avulsed traumatically?

Answer 17

during violent eversion of the foot, the tubercles of the 5th metatarsal bone can be avulsed

Question 18

What are the deep and superficial muscles int he posterior compartment?

Answer 18

Deep:
- popliteus 
- flexor hallucis longus
- tibialis posterior
- flexor digitorum longus
Superficial:
- gastrocnemius
- soleus
- plantaris

Question 19

Gastrocnemius (OINA)

Answer 19

O: lateral and medial femoral condyles
I: posterior calcaneus
N: tibial nerve
A: flexes knee; plantarflexes foot

Question 20

What do the superficial posterior muscles do?

Answer 20

help in walking, dancing, and standing on the toes

Question 21

What is tennis leg?

Answer 21

painful calf injury due to tearing of medial belly of gastrocnemius

Question 22

Soleus (OINA)

Answer 22

O: fibular head and soleal line of tibia
I: posterior calcaneus
N: tibial nerve
A: plantarflexes foot

Question 23

What does constantly wearing high heels do to your muscels?

Answer 23

women you continuously wear high heel shoes have shorter triceps surae and can experience transitory calf pain when they switch to flats

Question 24

How is the calcaneal tendon ruptured?

Answer 24

occurs in old age, or playing squash, or at the start of a 100 meter dash, due to ischemia

Question 25

Plantaris (OINA)

Answer 25

O: inferior lateral supracondylar line
I: posterior calcaneus
N: tibial nerve
A: weakly assits gastrocnemius

Question 26

What is special about plantaris tendon?

Answer 26

its tendon can be removed and used to repair other damaged tendon

Question 27

Popliteus (OINA)

Answer 27

O: lateral epicondyle of femur
I: superior posterior tibia
N: tibial nerve
A: flexes knee and rotates knee joint; unlocks knee at the beginning of flexion of the fully extended knee

Question 28

What are the actions of the popliteus?

Answer 28

• rotation is about 5 degrees
• when the knee is fully extended it is locked by the medial rotation of femur on tibia around a tight ACL
• popliteus unlocks the knee by laterally rotating the femur ont he weight-bearing tibial allowing relaxation of the ligaments and then flexion
• during this movement it also causes the lateral meniscus to be pulled out of the way of injury

Question 29

What are the characteristics of the deep posterior muscles?

Answer 29

• three deep posterior leg muscles
• all span the ankle joint
• two of them also flex the toes

Question 30

Flexor Hallucis Longus (OINA)

Answer 30

O: inferior 2/3 of posterior fibula; interosseous membrane
I: distal phalanx of hallux
N: tibial nerve
A: flexes hallus and plantarflexes foot

Question 31

How does the flexor hallucis longus, tibialis posterior, and flexor digitorum longus help in running?

Answer 31

Flexor digitorum/hallucis longus and tibialis help to maintain the medial longitudinal arch of foot.
Flexor hallucis longus is the “toe off” muscle during walking and running.
Flexor digitorum longus gives foot a grip while walking and running

Question 32

Tibialis Posterior (OINA)

Answer 32

O: interosseous membrane; posterior tibia and fibula
I: navicular, cuneiform, cuboid, and 2-4 metatarsals
N: tibial nerve
A: plantarflexes and inverts foot

Question 33

Flexor Digitorum Longus (OIN)A

Answer 33

O: middle posterior tibia
I: distal phalanges of lateral 4 digits
N: tibial nerve
A: flexes lateral 4 digits; plantarflexes foot

Question 34

What are the nerves of the posterior leg? What is their pathways and symptoms of damage?

Answer 34

Tibial nerve continues across ankle
- if damaged: weak plantarflexion; plantarflexion is accompined by eversion; loss of toe flexion
Common fibular nerve winds around head of fibula
- very frequently damaged
- if damaged: loss of eversion and dorsiflexion

Question 35

What are the nerves of the lateral and anterior leg? What is their pathways and symptoms of damage?

Answer 35

Common fibular nerve:
Superficial fibular (lateral)
- damage results in weak eversion
Deep fibular (anterior)
- damage results in loss of dorsiflexion (foot drop)

Question 36

What are the arteries of the knee and leg?

Answer 36

• “genu” means “knee” in Latin
• after giving off genicular arteries, popliteal artery divides into:
• • anterior tibial artery (goes to anterior compartment)
• • posterior tibial artery (stays in posterior compartment)
• – fibular artery