1. Chapter 8:Part 1 The Lower Extremity: Knee, Ankle, and Foot
KINESIOLOGY
Scientific Basis of Human Motion, 12th edition
Hamilton, Weimar & Luttgens
Presentation Created by
TK Koesterer, Ph.D., ATC
Humboldt State University
Revised by Hamilton & Weimar
McGraw-Hill/Irwin
Copyright © 2012 by The McGraw-Hill Companies, Inc. All rights reserved.

2. Objectives
1. Name, locate, & describe the structure & ligamentous reinforcements of the joints of the knee, ankle, and foot. 2. Name & demonstrate movements possible. 3. Name & locate muscles & muscle groups, and name their primary actions. 4. Analyze the fundamental movements with respect to joint & muscle actions. 5. Describe common athletic injuries.

3. THE KNEE JOINT: Structure
Fig 8.2
Hinge joint.
Two condyles of femur articulate with tibial plateaus.
Patella articulates with patellar surface of femur.
Fig 8.4
Menisci
Circular rims of fibrocartilage.
Lateral –an incomplete circle.
Medial – “C” shaped.
Thick peripheral borders, tapering to a thin inner edge.

4. Ligaments of the Knee
Fig 8.3
Lateral
Medial

5. Ligaments of the Knee
Lateral
Fig 8.6
Medial
Fig 8.5

6. Muscles of the Knee Joint
Anterior
Quadriceps Group
Rectus femoris
Vastus intermedius
Vastus lateralis
Vastus medialis
Posterior
Hamstring Group
Biceps femoris
Semimembranosus
Semitendinosus
Sartorius
Gracilis
Popliteus
Gastrocnemius

7. Muscles of the Knee Joint
Fig 8.7
Rectus Femoris
Function:
Powerful knee extensor.
Sartorius
Flexion and internal rotation in non-weight bearing.

8. Muscles of the Knee Joint
Vastus intermedius
Vastus lateralis
Vastus medialis
Function:
Powerful knee extensors.
Fig 8.8

9. Muscles of the Knee Joint
Fig 8.10
Biceps femoris
Function:
Flexes knee & external rotation of tibia in non-weight bearing.
Semimembranosus
Semitendinosus
Flexion and internal rotation in non-weight bearing.

10. Muscles of the Knee Joint
Gracilis
Function:
Flexes knee.
Slightly active in internal rotation of tibia when knee is flexed.
Popliteus
Helps flex knee (unlocks).
Internally rotates tibia.
Fig 8.11

11. Muscles of the Knee Joint
Fig 8.23
Gastrocnemius
Function:
Helps flex knee.
In weight bearing can help maintain knee extension.

12. Flexion: Hamstrings, sartorius, gracilis Extension: Quadriceps
MUSCULAR ANALYSIS OF FUNDAMENTAL MOVEMENTS OF THE LEG AT THE KNEE JOINT
Flexion: Hamstrings, sartorius, gracilis
Extension: Quadriceps
External Rotation: Biceps femoris
Can only occur when knee is flexed & non-weight bearing.
Internal Rotation: Semimembranosus, semitendinosus, popliteus

13. COMMON INJURIES OF THE LEG, KNEE AND ANKLE
The Leg: Tibial Stress Injuries
Often called “shin splints”.
An overuse injury.
Repeated microtears where tibialis posterior or anterior attaches to tibia, inflammation.
Sprains in interosseous membrane.
Tenderness & pain on medial surface of tibia.
Rest, softer surface and supporting the arch are best treatment.

14. COMMON INJURIES OF THE LEG, KNEE AND ANKLE
The Leg: Fracture
Most common among the young.
Most common to lower 2/3 of fibula.
May result in instability of ankle joint.
Severity based on bone displacement:
More displaced - more severe.
The Leg: Shin Contusions
Common based on exposed nature of tibia.
Usually from a direct blow.
May damage periosteum.
Shin guards are recommended in activities in which leg impacts are common.

15. COMMON INJURIES OF THE LEG, KNEE AND ANKLE
The Knee: Collateral Ligament Sprain
Direct blow to either side of knee.
Majority are blows from lateral side causing medial collateral ligament damage.
Depending on amount of force the following structures could be injured:
Medial collateral ligament
Medial meniscus
Anterior cruciate ligament
The Knee: Chondromalacia
Degeneration of cartilage on articulating surface of patella.
Pain, on movement, swelling, grating sensation.
Treatment through evaluation of lower body biomechanics, rehabilitative exercises, limiting activities.

16. COMMON INJURIES OF THE LEG, KNEE AND ANKLE
The Knee: Osgood Schlatter Disease
Due to repeated overuse of knee extensors.
Tearing or avulsion of epiphysis of tibial tuberosity.
Swelling, pain on activity & kneeling.
Treat with rest, ice, rehabilitative exercises.

17. THE ANKLE AND FOOT: Structure
The foot provides for support and propulsion.
Movements within the foot occur primarily at the subtalar and midtarsal joints.
The ankle serves to unite the foot and the leg. 17

18. Structure of the Ankle Hinge joint
Articulation of talus with malleoli of tibia & fibula.
Bound together by ligaments.
Fig 8.12
Tibia
Talus
Sustentaculum
tali
Calcaneous
Fibula 18

19. Ligamentous Reinforcement
Fig 8.14
Lateral side
Anterior talofibular
Calcaneofibular
Posterior talofibular
Medial side
Deltoid
Calcaneotibial
Anterior talotibial
Tibionavicular
Posterior talotibial
Plantar calcaneonavicular
Deltoid
a. Calcaneotibial
b. Anterior talotibial
Plantar calcaneonavicular
d. Posterior
talotibial
c. Tibionavicular
Fig 8.13 19

20. Structure of the Foot An elastic arched structure.
Fig 8.15
An elastic arched structure.
Talus is the keystone.
Comprised of two arches:
Longitudinal
Transverse 20

21. Structure of the Foot Longitudinal arch: Transverse arch:
Heel to heads of five metatarsals.
Supported by the plantar fascia.
Transverse arch:
Side-to-side concavity.
Anterior tarsal bones & metatarsals.
Fig 8.16 21

22. Subtalar Joint
Joint between underside of talus and upper & anterior aspects of calcaneus.
Plantar calcaneonavicular “spring ligament” helps support talus.
Fig 8.17b 22

23. Foot Joints
Midtarsal Joint (Chopart’s Joint): Consists of two articulations:
Calcaneocuboid: Nonaxial – permits only gliding.
Talonavicular: Modified ball-and-socket – permits restricted motion.
Tarsometatarsal Joints: Movements are gliding.
Intermetatarsal Joints: spreading or flattening.
Metatarsophalangeal Joints: Modified condyloid joints.
Interphalangeal Joints: Hinge joints. 23

24. Movements of Foot at the Ankle, Tarsal, & Toe Joints
Fig 8.20 24

25. MUSCLES OF THE ANKLE & FOOT
Location:
22 muscle of the ankle & foot are intrinsic.
11 muscles are extrinsic. 25

26. MUSCLES OF THE ANKLE & FOOT
Fig 8.21a
Tibialis Anterior
Function: dorsiflexes ankle & supinates foot.
Peroneus Brevis
Function: plantarflexes, everts.
Extensor Hallucis Longus
Extensor Hallucis Brevis
Function: extends great toe.
Extensor Digitorum Brevis
Function: extends toes. 26

27. MUSCLES OF THE ANKLE & FOOT
Fig 8.22
Extensor Digitorum Longus
Function: extends toes.
Peroneus Longus
Function: plantarflexes, everts, abducts.
Peroneus Tertius
Function: dorsiflexes & pronates. 27

28. MUSCLES OF THE ANKLE & FOOT
Fig 8.23
Gastrocnemius
Function: powerful plantar flexor.
Fast twitch.
Allows one to rise on toes, lift body weight.
Advantageous leverage. 28

29. MUSCLES OF THE ANKLE & FOOT
Fig 8.24
Soleus
Function: Strong ankle plantar flexor.
Slow twitch.
Postural, static plantar flexion. 29

30. MUSCLES OF THE ANKLE & FOOT
Fig 8.25
Tibialis Posterior
Function: plantar flexes tarsal joints, supination when foot is plantar flexed.
Helps holds up longitudinal arch. 30

31. MUSCLES OF THE ANKLE & FOOT
Fig 8.26
Flexor Digitorum Longus
Function: Flexes toes, plantar flexes, helps inversion.
Flexor Hallucis Longus
Function: flexes great toe, plantar flexes, helps inversion. 31

32. Intrinsic Muscles of the Foot
Fig 8.27 & 8.28 32

33. Intrinsic Muscles of the Foot
Fig 8.29 & 8.30 33

34. Muscular Analysis of Fundamental Movements: Ankle
Dorsiflexion: tibialis anterior, peroneus tertius, extensor digitorum longus, extensor hallucis longus.
Plantar flexion: gastrocnemius, soleus, peroneus.
Possible help from tibialis posterior, peroneus brevis, flexor digitorum longus, flexor hallucis. 34

35. Muscular Analysis of Fundamental Movements: Tarsal Joints
Dorsiflexion: same as ankle.
Plantar flexion: tibialis posterior, flexor digitorum longus, flexor hallucis longus, peroneus longus.
Supination: tibialis anterior (when foot is dorsiflexed) & tibialis posterior (when foot is plantar flexed).
Pronation: peroneus longus, brevis, & tertius. 35

36. Muscular Analysis of Fundamental Movements: Toes
Flexion: flexor digitorum longus and flexor hallucis longus.
Extension: extensor digitorum longus and extensor hallucis longus. 36

37. COMMON INJURIES OF THE LEG, KNEE AND ANKLE
The Ankle: Strain
Due to impact that forces ankle beyond normal range.
Results in tearing at myotendinous junction.
May cause pain, weakness, possible deformity. Potentially very debilitating. 37

38. COMMON INJURIES OF THE LEG, KNEE AND ANKLE
The Ankle: Sprains
Usually associated with forceful inversion of the foot.
In this case the lateral ligaments stretched or torn, or may rupture.
Results in pain, swelling, disability. 38

39. COMMON INJURIES OF THE LEG, KNEE AND ANKLE
The Ankle: Fracture
Same causes as ankle sprains.
The majority occur to malleoli.
More serious fractures sometimes dislocate. 39

40. COMMON INJURIES OF THE LEG, KNEE AND ANKLE
The Foot: Plantar Fasciitis
Pain and tenderness along the sole of the foot.
May be due to inflammation, micro tears, or rupture of the plantar fascia.
Is generally an overuse injury; lack of flexibility may be contributory.
Stretching has been shown to be helpful. 40