One of the Largest and Complex Joint

KNEE JOINT

•  One of the largest and complex joint.

•  Formed by lateral femorotibial, medial femorotibial and femoropatellar articulations.

•  Articular surfaces:

•  Condyles of femur

•  Condyles of tibia

•  Patella

•  LIGAMENTS:

•  Fibrous capsule:

•  It is thin and absent anteriorly where it is replaced by the tendon of quadriceps, patella and ligament patellae.

•  Fibrous capsule (external fibrous layer) Synovial membrane (Internal layer)

•  Fibrous layer →Make the intrinsic ligaments.

•  Attached → superior on femur (Proximal to articular area).

•  Posterior → Covers condyles + intercondylar fossa.

•  Inferior → margins of tibial plateau.

•  Coronary ligament and short lateral ligament are the parts of the fibrous capsule:

•  Fibrous capsule is being strengthened by

–  Medial and lateral patellar reticula (Anterior)

–  Iliotibial tract (Lateral)

–  Sartorius and semimembranous (Medial)

–  Oblique popliteal ligament (Posterior)

•  Opening → Leads to supra patellar bursa

–  Exit for popliteus tendon.

•  Synovial membrane → All the surface bounding the articular cavity (Joint cavity) Patella and menisci are covered.

•  Patellar ligament → (anterior ligament of knee joint). Also receives aponeurotic expansions of vastus medialis, vastus lateralis and deep fascia (Medial and lateral pattelar retinacula).

•  Medial collateral (Tibial collateral ligament → Medial epicondyle of femur to condyle of femur → superior part of medial surface of tibia.

•  Lateral collateral (Fibular collateral ligament Lateral epicondyle → lateral surface of head of fibula.

•  Oblique popliteal ligament → Expansion of semimembranosus from medial tibial condyle to lateral femoral condyle.

•  Arcuate popliteal ligament → Posterior aspect of fibula → spreads to knee joint.

•  Intra capsular ligament:

•  Cruciate → Crossing each other

•  Out side the synovial cavity

•  Below the capsule

•  Anterior cruciate ligament:

•  Anterior intercondylar area of tibia

•  To posterior surface of medial side of lateral condyle and tibia. Prevents → Posterior displacement of femur.

•  Posterior cruciate ligament:

•  Posterior intercondylar area prevents → anterior displacement of femur attached on anterior part of lateral surface of medial condyle

•  Menisci → Fibro cartilaginous plates deepens the articular surface and play a role in shock absorption.

•  Coronary ligament portions of joint capsule between the meniscal margins and tibial condyles.

•  Transverse Ligament → Between the anterior edges of menisci

•  Anastomosis around knee joint:

•  Femoral / Sciatic / obturator nerve

•  Locking and unlocking of knee joint

•  Flexion → Biceps, Semimembranosus, Semitendinosus, Gracilis, Sartorius, Popliteaus, Gastrocnemius

•  Extension → Quadriceps femoris, tensor fascia lata.

•  Medial rotation → Popliteus, semis (Membranosus and tendosus) sartorius gracillis.

•  Lateral rotation → Biceps femoris

•  Articular surfaces are not congruent (Tibial condyles are small)

•  Leg may be abnormally abducted and adducted (Rickets etc).

•  Osteoarthritis, aspiration of fluid.

•  Arthroscopy

•  Injury to mensci, ligaments etc.