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Presented byShubham Rao
Knee Joint
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The Knee:
The largest and most complex joint structure Transmit Loads Participate in motion
Aids conservation of momentum Provides a force couple for body activities
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Definitions:
Kinematics is the study of movement withoutreference to forces
Kinetics is the study of movement withreference to forces
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Anatomy of the knee
3 Bones
Tibia, Femur, Patella 3 Compartments Medial, Lateral, Patellofemoral
4 Ligaments MCL, LCL, ACL, PCL 2 Menisci
Articular Cartilage
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The Knee Joint
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Menisci Functions
Deepen the articulation
Increase area of contact Shock absorption a skier lands from a jump
Increase stability Cups the femoral condyle Nutrition of cartilage
Sweeping synovial fluid across joint
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Range of Motion
Three different planes inwhich movements of theknee takes place
1. Sagittal plane2. Frontal plane3. Transverse plane
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Tibia-femoral motion in theTransverse plane Influenced by knee position in Sagittal plane
Ex. If knee is in full extension rotation isrestricted by interlocking of condyles withtibia
Rotation increases as the knee is flexed maximum 90 degree flexion Beyond 90 degree decreases, due to soft tissue restriction
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Tibia-femoral motion in the frontalplane Abduction and Adduction is also affected by the
amount of knee flexion Ex. Full extension precludes motion
Vulgus /Varus
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Types of motion at knee joint
Rolling Motion
Initiates flexion
Gliding Motion
Occurs at end of flexion
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Gliding Motion
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Rolling Motion
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Instantaneous Center of RotationICR "If one rigid body rotates
about another rigid body,
its motion at any instantcan be described by apoint or axis of rotationcalled the instantaneouscenter of rotation.
For normal knees Pathway of ICR is
semicircular Located on the femoral
condyles
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Joint Contact Forces
We would haveequal distributionof forces w/o any
varus or valgusstresses
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Patellar Kinematics
Patella or the knee cap is directly in contact with the femoral
condyles in flexion It is said to be lateral side dominant dominant Greater surface area of contact on the lateralside as opposed to the medial
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