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Brunnstrom’s Clinical Kinesiology Sixth Edition
CHAPTER 10
Knee
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Introduction
 Is the largest joint in body; frequently injured
because it is positioned between two long bony
levers
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Bones
 Femur
 Tibia
 Tibial tuberosity
 Fibula
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
 Patella
Bones
 Largest sesamoid bone in body
 Multiple functions:
 Increase internal moment arm of quadriceps
 Centralize force of quadriceps pull
 Reduce tendon and friction forces
 Contribute to overall knee stability
 Provide bony protection
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Joints
 Tibiofemoral (knee)
 Largest joint in body
 Hinge/ginglymus
 “trocho-ginglymus”?
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Joints
 Tibiofemoral—menisci
 Wedge shaped—thickest toward outer rim
 Move anteriorly with knee extension, posteriorly
with knee flexion
 Functions:
 Deepen socket and improve congruency
 Absorb and distribute forces/increase surface area
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Joints
 Tibiofemoral—menisci
 Functions:
 Promote lubrication of joint
 Prevent joint capsule from intruding into joint space
 Partially protect against excessive motion
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Joints
 Tibiofemoral—collateral ligaments
 Origins are offset superiorly and posteriorly
 Causes the collaterals to tighten with knee extension
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Joints
 Tibiofemoral—collateral ligaments
 Lateral collateral ligament
 Has distinct structure—rope- or cord-like
 Is located outside of joint capsule—”extracapsular”
 Provides primary restraint when the knee is subjected
to laterally directed forces
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Joints
 Tibiofemoral—cruciate ligaments
 Intracapsular; extrasynovial
 Named by appearance of “cross” they create
 Maintain near same length throughout range of
motion (ROM)
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Joints
 Tibiofemoral—cruciate ligaments
 Anterior cruciate
 Anterior medial–posterior lateral bundles
 Resists anterior translation of tibia on femur
 Posterior cruciate
 Anterior lateral–posterior medial bundles
 Resists posterior translation of tibia on femur
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Joints
 Tibiofemoral—osteokinematics (sagittal)
 Flexion
 On average, to 135°
 Limited by soft tissue approximation
 Extension
 To 0°; often hyperextends but not past 15°
 Limited by capsular tightening
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Joints
 Tibiofemoral—osteokinematics (transverse)
 Axial rotation
 Occurs when knee is flexed
 At 90° of flexion, 45° total (2:1; lateral:medial)
 Occurs about a vertical or longitudinal axis
 Normal end feels are firm—capsular
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Joints
 Patellofemoral—Q angle
 Females > Q angle compared with males
 Genu varum—valgum
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Muscles
 Knee extensors
 Quadriceps femoris
 Vastus lateralis
 Vastus medialis oblique and vastus medialis longus
 Vastus intermedius
 Rectus femoris
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Muscles
 Knee flexors
 Hamstrings
 Gastrocnemius—plantaris—popliteus
 Gracilis
 Sartorius
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Functions of Knee Muscles
 Knee extensors
 Function to:
 Stabilize—isometric
 Decelerate—eccentric
 Accelerate—concentric
 Large and powerful muscle group
 Necessary to match demands of ADLs and recreational
activities
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Functions of Knee Muscles
 Knee extensors
 Rectus femoris
 Biarticular muscle crossing both hip and knee
 Vastus medialis
 VMO—fiber direction: 50–55°; stabilize patella
 VML—fiber direction: 15–18°
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Functions of Knee Muscles
 Knee flexors
 Hamstrings
 Little force required by these muscles in open chain
 Closed chain—great forces required particularly at hip
 Dynamically restrain anterior tibial translation
 Function to assist and decelerate rotation
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Functions of Knee Muscles
 One and two joint muscles acting at the knee
 Majority of muscles that cross knee are biarticular.
 Multijoint muscles:
 Are more efficient
 Produce motion in multiple planes
 Seldom act at both joints simultaneously
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Functions of Knee Muscles
 One and two joint muscles acting at the knee
 Knee flexion with hip extension
 Hamstrings—active insufficiency
 Rectus femoris—passive insufficiency
 Knee extension with hip flexion
 Hamstrings—passive insufficiency
 Rectus femoris—active insufficiency
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Functions of Knee Muscles
 One and two joint muscles acting at the knee
 Knee flexion with hip flexion
 Hamstrings—elongated at hip; shortened at knee
 Rectus femoris—elongated at knee; shortened at hip
 Knee extension with hip extension
 Hamstrings—elongated at knee; shortened at hip
 Rectus femoris—elongated at hip; shortened at knee
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Joint Forces
 Tibiofemoral
 Forces across joint increase with activity.
 Shear stresses (A-P) are also experienced with
knee range.
 Anterior cruciate ligament (ACL) and hamstrings restrict
anterior tibial translation.
 Posterior cruciate ligament (PCL) and quadriceps
restrict posterior tibial translation.
 Excessive forces over time may promote
degenerative joint disease.
Copyright © 2012 F.A. Davis Company
Brunnstrom’s Clinical Kinesiology Sixth Edition
Joint Forces
 Torque of muscles acting at knee
 Hamstring/quadriceps ratio
 Established with isokinetic dynamometry
 Typically quantified at 60°/second during a concentric
contraction of both muscle groups
 Normal ratio—2:3, or 66%
Copyright © 2012 F.A. Davis Company