course: introduction to exercise science level i...
TRANSCRIPT
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