Session 4-Part 2: The Lower Extremity: Knee, Ankle, & Foot Region

COURSE: Introduction to Exercise Science Level I (Kinesiology)

Presentation Created byKen Baldwin, M.Ed

Copyright © EFS Inc. All Rights Reserved.

Objectives

1. Name, locate, & describe the structures of the Knee, Ankle, and Foot area

2. Analyze the fundamental movements with respect to Knee, Ankle, and Foot joint & muscle actions

3. Describe common injuries to Knee, Ankle, and Foot area

THE KNEE JOINT: Structure• Hinge joint• Two condyles of femur articulate with tibial

plateaus • Patella articulates with patella surface of femur

Fig 8.2anterior

THE KNEE JOINT Structure

• Menisci are circular rims of fibrocartilage

• Lateral – is an incomplete circle

• Medial – “C” shaped- loose fitting

• Thick peripheral borders & thin inner edge

• Transverse ligament-Connects medial & Lateral meniscus

Fig 8.4

The Knee Joint Structure Meniscus & Muscular Attachments

• Medial Meniscus- Muscular attachement- Semimembranosus Muscle

• Lateral Meniscus- Muscular Attachement- Popliteus muscle

Ligaments of the Knee

Fig 8.3

Ligaments of the Knee

• Tibial (Medial) Collateral Ligament- attaches to the medial meniscusIf a medial injury occurs, sometimes the medial meniscus, the tibial collateral ligament, and the ACL can get injured.

• Fibular (Lateral) Collateral Ligament- does not attach to the lateral meniscus

Ligaments of the Knee

Fig 8.5

Ligaments of the Knee

• ACL-attaches to the anterior tibia, passes under transverse ligament, attaches to inner aspect of lateral femoral condyle. Restrains anterior displacement of tibia on femur

• PCL- attaches to posterior tibia, and attaches to inner aspect of medial femoral condyle. Halts posterior displacement of tibia on femur

• ACL & PCL - cross each other, hence “cruciate”

Positions of the Knee

• Genu Valgum- Knock kneed-medial collatoral ligament stressed, lateral menisicus increased friction.

• Genu Varus- Bow Legged-Lateral collatoral ligment stresses, medial meniscus increased friction.

Movements of the Knee

• Flexion and Extension- Combination of Rolling, Gliding (during flexion condyles move anteriorly) & Spinning

1. Leg Extension- Avoid close-packed or locked position, stop short of 15° of full extension. Note-Design of machine

2. Squat- 90° collateral ligaments most laxed. Avoid shifting with lateral movement. Prevent internal rotation of knee & compression on cartilage & ligaments.

• Rotation-Pivot- limited, non-weight bearing

Movements

Fig 8.6

FlexionExtension

Internal rotationExternal rotation

Muscles of the Knee Joint

AnteriorQuadriceps Group

Rectus femorisVastus intermedius Vatus lateralisVastus medialis

PosteriorHamstring Group

Biceps femorisSemimembranosusSemitendinosus

SartoriusGracilisPopliteusGastrocnemius

Rectus FemorisFunction: • Powerful knee extensionSartoriusFunction: • Flexion and internal

rotation in non-weight bearing

Fig 8.7

Vastus intermediusVastus lateralisVastus medialisFunction: • Powerful knee extension

Fig 8.8

Q Angle- Pull on the Patella

• The Q Angle determines the pull on the patella.

• Q Angle determined between the ASIS & center of the patella, then from the tibial tuberosity to the center of the patella.

• Average angle is 8 to 17°, higher Q in female• Increased Q angle can increase

patellafemoral problems.• “Off Center Line of Pull”

Fig 8.10

Biceps femorisFunction: • Flexes knee & external

rotation of tibia in non- weight bearing

SemimembranosusSemitendinosusFunction: • Flexion and internal

rotation in non-weight bearing

Fig 8.11

GracilisFunction: • Flexes knee • Slightly active in internal

rotation of tibia when knee is flexed

PopliteusFunction: • Internally rotates tibia• Initiates flexion of knee• Unlocks-Extended Knee

Locking/Unlocking Knee

• Locking or Screw Home Mechanism (Automatic)-final rotation in knee extension brings knee into close-packed or locked position. Ligaments & mensici are taunt.

• Initiation of Flexion- a medially rotated femur cannot flex in sagittal plane, must laterally rotate.

Fig 8.23

GastrocnemiusFunction: • Helps flex knee• Primary muscle of ankle

joint• Acts as a large posterior

ligament• Weight bearing can

support & help maintain knee extension

• Jumping & running

MUSCULAR ANALYSIS OF FUNDAMENTAL MOVEMENTS OF THE

LEG AT THE KNEE JOINT• Flexion: Hamstrings, sartorius, gracilis.etc..• Extension: Quadriceps• External Rotation: Biceps femoris

– Can only occur when knee is flexed & non- weight bearing

• Internal Rotation: Semimembranosus, Semitendinosus, popliteus, gracilis, sartorius– Can only occur when knee is flexed & non-

weight bearing

THE ANKLE AND THE FOOT Structure

• Hinge joint• Dorsiflexion/plantar

flexion• Articulation of talus

with distal ends of tibia & fibula called the Talocrual joint

Fig 8.12

Proximal/Distal Tibiofibular Joints

• Proximal Tibiofibular joint- Synovial Joint, small Range of motion

• Distal Tibiofibular joint- Fibroandipose tissue, non-union

• Interosseus membrane- between tibia and fibula

Ligamentous Reinforcement

Lateral side• Anterior talofibular• Calcaneofibular• Posterior talofibular Fig 8.14

Ligamentous Reinforcement

Medial side• Deltoid

– Calcaneotibial– Anterior talotibial– Tibionavicular

Posterior talotibial • Plantar

calcaneonavicular

Fig 8.13

DeltoidCalcaneotibial

Anterior talotibial

Tibionavicular(Posterior talotibial )l

Plantar calcaneonavicular

Structure of the Foot

• An elastic arched structure– Keystone being

the talus Fig 8.15

Structure of the Foot• 7 Tarsal Bones• Longitudinal arch

Heel to heads of five metatarsals

• Transverse archSide-to-side concavity

• Bones & ligaments make arch, muscles are secondary

• Flat feet-more muscle activity

Fig 8.16

Subtalar Joint • Underside of talus and upper & anterior aspects

of calcaneus- movement of ankle occur here, supination and pronation

• Plantar calcaneonavicular “Spring ligament” helps support talus

Fig 8.17b

Plantar Fascia

• Muscles and ligaments covered by fascia or plantar aponeurosis

• Strong and fibrous-binding rod for longitudinal arch

Foot Joints

Midtarsal Joints: Nonaxial – permits only gliding• Modified ball-and-socket – permits restricted

motion- movements of ankle occur hereTarsometatarsal Joints: Movements are gliding Intermetatarsal Joints: spreading or flattening Metatarsophalangeal Joints: Modified condyloid

jointInterphalangeal Joints: Hinge joints

Movements of Foot at the Ankle, Tarsal, & Toe Joints

Fig 8.20

DorsiflexionPlantarflexion

InversionEversion

MUSCLES OF THE ANKLE & FOOT

Location:• 22 muscle of the ankle & foot are intrinsic• 11 muscles are extrinsic

Tibialis AnteriorFunction: dorsiflexes ankle &

supinates footPeroneus BrevisFunction: plantarflexes, evertsExtensor Hallucis LongusExtensor Hallucis BrevisFunction: extends great toeExtensor Digitorum BrevisFunction: extends toes

Fig 8.21a

Extensor Digitorum Longus

Function: extends toesPeroneus LongusFunction: plantarflexes,

everts, abductsPeroneus TertiusFunction: dorsiflexes &

pronates

Fig 8.22

GastrocnemiusFunction: powerful

plantar flexor• Fast twitch• Dynamic plantar

flexorFig 8.23

SoleusFunction: plantar flexes • Slow twitch• Postural, static

plantar flexion

Fig 8.24

Tibialis PosteriorFunction: plantar

flexes, supination• Helps holds up

longitudinal arch

Fig 8.25

Flexor Digitorum Longus

Function: Flexes toes, plantar flexes, helps inversion

Flexor Hallucis Longus

Function: flexes great toe, plantar flexes, helps inversion

Fig 8.26

Intrinsic Muscles of the Foot

Fig 8.27 & 8.28

Intrinsic Muscles of the Foot

Fig 8.29 & 8.30

Muscular Analysis of Fundamental Movements of the 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

Muscular Analysis of Fundamental Movements of the Tarsal Joints

• Dorsiflexion: same as ankle• Plantar flexion: tibialis posterior, flexor

digitorum longus, flexor hallucis longus, peroneus longus

• Supination: tibialis anterior (when foot dorsiflexed)& tibialis posterior (when foot plantar flexed)

• Pronation: peroneus longus, brevis, & tertius

Muscular Analysis of Fundamental Movements of the Toes

• Flexion: flexor digitorum longus and flexor hallucis longus

• Extension: extensor digitorum longus and extensor hallucis longus

COMMON INJURIES OF THE LEG, KNEE AND ANKLE

• The Leg: Shin Splints-Overuse injury• Repeated microtears where tibialis posterior

or anterior attaches to tibia• Sprains in interosseous membrane• Tenderness & pain on medial surface of tibia

The Leg: Fracture• Most common to lower 2/3 of fibula-• Direct blow- Most common to lower 2/3 of

fibula• May result in instability of ankle joint; Pain,

Possible deformity

The Knee: Medial Collateral Ligament Sprain

Cause: Direct blow to lateral aspect of knee- knee is then adducted & medially rotated. Can occur from intense movement.Depending amount of force the following structures could be injured

• Medial collateral ligament• Medial meniscus• Anterior Cruciate Ligament

The Knee: ChondromalaciaUnknown, Overuse?• Degeneration of cartilage on articulating

surface of patella• Pain, on movement, swelling, grating

sensation• Evaluation of lower body biomechanics,

rehabilitative exercises, limiting activities

The Ankle: Strain

Cause: Landing form jumping• tearing at myotendinous junction Example-

Achilles Tendon

The Ankle: Sprains

• Forceful inversion of the foot• Lateral side is the most common• lateral ligaments stretched or torn• Can be as bad as a broken ankle

The Ankle: Fracture

• Same as ankle sprains• majority occur to malleoli• More serious fracture sometimes dislocate