Lecture 20: Leg

Question 0

Slide 9 and 10

Distal joints of the leg & foot

Answer 0

O

Question 1

Tell me about the tibia
And the fibula
How are they joined together

Answer 1

Large, weight-bearing bone. 
• Large proximal facets for articulation 
with femur 
• Distal facet is cup-shaped and 
articulates with talus. 
• Tibial tuberosity => insertion site for 
patellar ligament. 
• Medial malleolus => prominence on 
medial aspect of ankle. 

FIBULA
• Long slender bone.
• Primary function is for muscle attachment (not load bearing!).
• Projects further distally than the tibia.
• Lateral malleolus => prominence on the lateral aspect of ankle.
• Fracture of neck may damage common fibular (peroneal) nerve.

Tibia and fibula joined together in life by an interosseous membrane

Question 2

Sprained ankle tell me bout it.
Which way it normally happens and why?
Slide 11

Answer 2

Usually (90%) INVERSION “roll to side” injury
• Involves weaker lateral collateral ligaments (which resist inversion of foot)
• 1.Anterior talofibular lig.
• 2. Calcaneofibular lig.
• 3. Posterior talofibular lig.

Question 3

Learn slide 14 and 15

Compartments of the leg

Answer 3

H

Question 4

What are the muscles in the anterior compartment of the leg and what is their blood supply and nerve innervation.
Slide 16

Answer 4

H

Question 5

Tibial is anterior slide 18

Answer 5

Proximal attachment: Lateral condyle and superior half of lateral surface of tibia
• Distal attachment: Medial and inferior surfaces of medial cuneiform and base of 1st metatarsal
• Innervation: Deep fibular nerve
• Action: Dorsiflexes foot at ankle and inverts foot

Question 6

Tibialis anterior tendon

Slide 19

Answer 6

Most medial & superficial dorsiflexor
• Strongest dorsiflexor
• Anterior to ankle
• Secured by inferior extensor retinaculum
• Attached to medial & inferior surfaces of medial cuneiform & base of 1st metatarsal

Question 7

Extensor hallucis longus

20 and the tendon on 21

Answer 7

Proximal attachment: Middle part of anterior surface of fibula and interosseous membrane
• Distal attachment: Dorsal aspect of base of distal phalanx of big toe
• Innervation: Deep fibular nerve
• Action: Extends big toe and dorsiflexes foot @ ankle

Tendon:
Extensor hallucis longus lies deep between tibialis anterior and extensor digitorum longus muscles
Passes anterior to ankle
Tendon secured by extensor retinacula
Inserts at base of distal phalanx of big toe

Question 8

Extensor digitorum longus slide 22

Tendon on slide 23

Answer 8

Proximal attachment: Lateral condyle of tibia & superior 3⁄4 of anterior surface of interosseous membrane & fibula
• Distal attachment: Middle & distal phalanges of digits 2-5
• Innervation: Deep fibular nerve
• Action: Extends digits 2-5 & dorsiflexes foot @ ankle

Question 9

Fibularis (peroneus) tertius slide 24

Tendon on slide 25

Answer 9

Proximal attachment: Inferior 1/3 of anterior surface of fibula & interosseous membrane
• Distal attachment: Dorsum of base of 5th metatarsal
• Innervation: Deep fibular nerve
• Action:Dorsiflexes foot @ ankle & aids eversion of foot

Question 10

Lateral compartment of the leg

Slide 26

Answer 10

Primarily able to evert the foot and can weakly plantarflex the foot at the ankle.
• Blood supply = Fibular artery (branch of posterior tibial artery)
• Innervation = Superficial fibular nerve
• Muscles =
• Fibularis longus
• Fibularis brevis

Question 11

Fibularis longus

Slide 27

Answer 11

Proximal attachment: Head and superior 2/3 of lateral surface of fibula
• Distal attachment: Base of 1st metatarsal & medial cuneiform
• Innervation: Superficial fibular nerve
• Action: Everts foot & weakly plantarflexes foot @ ankle

Question 12

Fibularis brevis
28
Tendons of both the fibularis muscles
Slide 29

Answer 12

Proximal attachment: Inferior 2/3 of lateral surface of fibula

• Distal attachment: Dorsal surface of tuberosity of lateral side of 5th metatarsal
• Innervation: Superficial fibular nerve
• Action: Everts foot & weakly plantarflexes foot @ ankle

Tendons
Fibularis longus is longer and more superficial • Evertors of the foot (elevate lateral margin of foot) acting at transverse tarsal joints

Question 13

Name the muscles in the posterior compartment

Their blood supply and nerve innervation

Answer 13

Primarily flexors of the foot at the ankle (plantarflexion) and flexors of toes.

• Blood supply = Posterior tibial artery
• Innervation = Tibial nerve
• Gastrocnemius
• Soleus
• Plantaris
• Popliteus
• Flexor hallucis longus
• Flexor digitorum longus
• Tibialis posterior

Question 14

Gastrocnemius

31

Answer 14

Proximal attachment: Lateral head: lateral aspect of lateral condyle of femur. Medial head: popliteal surface of femur, superior to medial condyle
• Distal attachment: Calcaneal tendon  posterior calcaneous
• Innervation: Tibial nerve
• Action:Plantarflexes foot @ ankle; flexes leg @ knee joint

Question 15

Soleus

32

Answer 15

Proximal attachment: Posterior aspect of head of fibula, superior ¼ of posterior surface of fibula, soleal line, medial border of tibia.
• Distal attachment: Calcaneal tendon  posterior calcaneous
• Innervation: Tibial nerve
• Action: Plantarflexes foot @ ankle; steadies leg on foot

Question 16

Plantaris

33

Answer 16

Proximal attachment: Inferior end of lateral supracondylar line of femur and oblique popliteal ligament
• Distal attachment: Calcaneal tendon  posterior calcaneous
• Innervation: Tibial nerve
• Action: Weakly assists gastrocnemius in plantarflexing foot @ ankle and flexing knee

Question 17

Popliteus

34

Answer 17

Proximal attachment: Lateral condyle of femur and lateral meniscus
• Distal attachment: Posterior surface of tibia, superior to soleal line
• Innervation: Tibial nerve
• Action: Weakly flexes leg at knee and unlocks it.

Question 18

Flexor hallucis longus

35

Answer 18

Proximal attachment: Inferior 2/3 of posterior surface of fibula and inferior interosseous membrane
• Distal attachment: Base of distal phalanx of big toe
• Innervation: Tibial nerve
• Action: Flexes big toe @ all joints & plantarflexes foot @ anklel supports longitudinal arches of foot

Question 19

Flexor digitorum longus

37 and tendon shown on slide 38

Answer 19

Proximal attachment: Medial part of posterior surface of tibia inferior to soleal line, and from fascia covering tibialis posterior

• Distal attachment: Bases of distal phalanges of digits 2-5
• Innervation: Tibial nerve
• Action: Flexes digits 2-5 & plantarflexes foot @ anklel supports longitudinal arches of foot

Question 20

Tibialis posterior

39

Answer 20

Proximal attachment: Interosseous membrane, posterior surface of tibia inferior to soleal line, and posterior surface of fibula

• Distal attachment: Tuberosity of navicular, cuneiform and cuboid and bases of metatarsals 2, 3, 4
• Innervation: Tibial nerve
• Action: Plantarflexes foot @ ankle and inverts foot

Question 21

The flexor tendons

Slide 40

Answer 21

H

Question 22

Blood supply of the leg

41-44

Answer 22

• Popliteal artery
• Posterior tibial artery
• Anterior tibial artery
• Fibular artery

Question 23

Haven’t finished

Answer 23

J