Big&jointsystems:&&...
Transcript of Big&jointsystems:&&...
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Big joint systems: the knee and the hip
Li9erature
• Biomechanics of the Knee: N&F chapter 7, E&S chapter 8
• Biomechanics of the Hip: N&F chapter 8, S&N&M&W chapter 7
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ClassificaNon of joints
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Hinge joint/ Gångjärnsled e.g. finger and toe joints
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Pivot or trochoid joint/ Vrid-‐ eller rota3onsled e.g. proximal radio-‐ulnar joint
1-‐dimensional
2-‐dimensional
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Ellipsoid joint/ äggled e.g. the wrist
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Saddle joint/ sadelled e.g. the base joint of the thumb
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Extension Flexion
Locking joint/ Spriralled e.g. the knee and elbow joints
3-‐dimensional
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Ball and socket joint/ Kulled e.g. hip and shoulder joints
lateral ligament
Mechanics of the knee
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Anterior view without the patella
Muscles around the knee
Anterior view Posterior view
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Degrees of moNon in the knee Proximal-‐distal translaNon internal/external rotaNon
AdducNon-‐abducNon rotaNon
Ligaments and menisci
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Range of Nbiofemoral joint moNon
Extension to flexion while: -‐ walking 0-‐67o -‐ climbing stairs 0-‐83o
-‐ descending stairs 0-‐90o -‐ si]ng down 0-‐93o
-‐ tying a shoe 0-‐106o -‐ li^ing an object 0-‐117o
How big forces do occur in the knee? Ex: StaNc analysis of stair climbing
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Known: • Body weight W • contact point foot-‐step • direcFon of the force in the
patellar tendon, P • contact point in the femur-‐
Fbia joint Derive: • magnitude of the force P in
the patellar tendon • magnitude and direcFon of
the contact force in the femur-‐Fbia joint
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IllustraNon of knee moNon
• MoNon in the knee joint: h9p://www.youtube.com/watch?v=H3YgbJLbIXk&feature=related
Mechanics of the hip
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Muscles around the hip
Abductor muscles Adductor muscles
Movements of the hip joint
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1. Acetabulum (ledpanna) 2. Gluteus medius 3. Caput femoris (ledhuvud) 4. Collum femoris (lårbenshals) 5. Corpus femoris 6. Labrum
ilium
Iliac crest (hö>benskam)
sacrum
coccyx
Ischium (siAben)
Trocanter major
h9p://www.youtube.com/watch?v=qlCvKEOZtpo (nice illustraNons of the moNon in the hip)
Neck-‐sha^ angle
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Arthrosis
StaFc analysis of the forces in the hip during single-‐leg stance
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Known: • mass of one leg is 1/6 of the
total body mass • the line of acNon and point of
applicaNon for the abductor muscle force, M
• contact point in the hip, i.e. the point where the joint reacNon force J is applied
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IllustraFve exercises for the lectures