Knee Joint Flashcards
Name and classify
Modified synovial hinge joint
Bones
Patella - largest sesamoid bone
Femoral condyle - lateral and medial; large, articular prominence at distal end
Tibial plateau
Cartilage
Hyaline cartilage - reduce friction and shock absorbing
Additional features
Meniscus - Fibrocartilage, crescent shaped, supported by coronary ligaments, locate distal head of femur, congruence
Infrapatella bursa - cushioning the knee during kneeing
Suprapatella bursa - facilitates movement of quadriceps tendons
Infrapatella fat pad - behind patella ligament, shock absorber, facilitates movement of patella tendon
Capsule
Contains the whole joint
Attached to articular margins
Contains patella anteriorly
Not fibrous anteriorly - patellar retinaculum
Synovial membrane
Lines capsule
Secretes synovial fluid - lubricates, removes waste and provides nutrients for cartilage
Synovium - bathes area of femoral condyle
ACL and PCL are intracapsular by extrasynovial
Ligaments
Anterior cruciate ligament (ACL) - limits anterior and posterior movement and dislocation
Posterior cruciate ligament (PCL) - limits anterior and posterior movement and dislocation
Medial collateral ligament (MCL) - larger, medial epicondyle to medial tibial condyle, blends with the joint capsule and edge of meniscus, prevent rocking
Lateral collateral ligament (LCL) - smaller, lateral epicondyle to head of fibula, prevent rocking
Degrees of freedom
1 degree
2 degrees as rotation into closed-packed position
Movements
Flexion
Extension
Some medial and lateral rotation
Blood supply
Branched from femoral artery
Popliteal artery
Tibial artery
Anastomosis - alternative routes
Nerve supply
Branches of obturator, femoral, sciatic nerves
Muscles - flexors
Semimembranosus
Semitendinosus
Biceps femoris
Gastrocnemius
Muscles - extensors
Rectus femoris
Vastus medialis
Vastus lateralis
Vastus medialis
Muscles - medial rotators
Semimembranosus
Semitendinosus
Sartorius
Gracilis
Popliteus
Muscles - lateral rotators
Biceps femoris
