The Knee Flashcards
(20 cards)
Two articulations at the knee?
Tibiofemoral joint and patellofemoral joint
Medial patellofemoral ligament vs lateral patellofemoral ligament
Medial- thickest band in medial retinaculum
Lateral patellofemoral ligament - ITB to lateral patella
Role of knee ligaments?
Varus vs valgus?
Limit excessive knee extension
Varus- adduction of tibia
Val his - abduction of the tibia
A/P displacemf if tibia relative to femur
M/L rotation of tibia relative to femur
The MCL restricts what motion?
Taut in what?
Secondary role?
Excessive valgus in addition to medial and tibial rotation
Extension
Resisting anteriorly translation of tibia in femur
What is the primary restraint of the LCL?
Taut in what?
Varus stress and limits excessive lateral rotation
Helps to prevent posterolateral rotary instability
Taut in full extension
Primary restraint of the ACL?
What bundles are taut
Anterior translation of tibia on femur
PLB most taut in full extension
AMB more taut beyond 15 degrees of knee flexion
Most ACL injuries occur when knee is?
Slightly flexed and in a valgus position combines with anterior tibial translation
Muscles that act to translate tibia anterior? Posterior?
Soleus can resist anterior translation if?
Anteriorly- quad and gastroc
Posterior- hamstrings and Soleus
Foot is in ground
What motion resisted for PCL?
Bundles taut when?
Posterior tibial displacement
PMB taut near full extension
ALB taut at 80-90 deg of knee flexion
What are the extrasynovial bursae?
Pre patellar
Infrapatellar
Deep infrapatellar and fat pad
Normal Ext/Flx range?
Walking?
Stairs?
Sit to stand?
5-0-140 degrees
Walking 60-70
Stairs requires 80
Sit to stand 90
What are the coupled motion of the knee?
Terminal knee extension is accompanied by lateral rotation (open chain)
Flexion requires unlocking from Popliteus medial rotation of tibia (open chain) or lateral rotation of femur (closed chain )
Knee Flexor Muscles?
Hamstrings, sartorious, gracilis, Popliteus, gastrocnemius and Plantaris
Medial group produces? And lateral group produces?
All are 2 joint muscles EXCEPT?
What does the pes anserine resist?
Medial group produces Varus, lateral group valgus moments
Popliteus, and short head of biceps
Tendons resist valgus stresses and provide dynamic anteromedial stability
What two muscles can influence knee extension in weight bearing?
Glute max and Soleus
What is knee extensor muscle?
Resultant pull of quadriceps lateral and anterior?
Quadriceps
Lateral- 7-10 deg lateral and 3-r degrees anterior
Patella Alta vs patella baja?
Alta- longer and higher on femur
Baja- shorter and lower on femur
Patellofemoral joint stresses walking and running?
Walking- 25-50% wb
Running- 5-6x body weight
