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.

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.

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.

Ligaments of the Knee Fig 8.3 Lateral Medial

Ligaments of the Knee Lateral Fig 8.6 Medial Fig 8.5

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

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

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

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.

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

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

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

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.

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.

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.

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.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Intrinsic Muscles of the Foot Fig 8.27 & 8.28 32

Intrinsic Muscles of the Foot Fig 8.29 & 8.30 33

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

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

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

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

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

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

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