Knee joint

KNEE JOINT

1. KNEE JOINT By: RAJNISH KUMAR CiMS Bilaspur

2. KnEe JOINT: Synovial joint of condylar variety Knee Joint is largest and most complex joint in the body It consist of 3 joints: Medial condylar Joint : Between medial condyle of femur and medial condyle of tibia. Lateral condylar Joint : Between lateral condyle of femur and lateral condyle of tibia. Patellofemoral Joint : Between the patella and pateller surface of femur

3. Articular surface Articular surface of knee joint: Condyles of femur Patella Condyles of tibia

4. LIGAMENTS Fibrous (Articular) Capsule Anterior cruciate ligament P osterior cruciate ligament   M edial collateral ligament  or  T ibial collateral ligament L ateral collateral ligament or Fibular collateral ligament   Medial Meniscus Lateral Meniscus Oblique Popliteal ligament Arcuate Popliteal ligament Medial Meniscus Lateral Meniscus Ligamentum Patellae

5. Fibrous (Articular) Capsule C ommonly referred to as the  capsular ligament Deficient anteriorlly Anteriolaterally strengthened by Lateral pateller ligament and Anteromedilly Medial patellar ligament

6. Anterior cruciate ligament The Anterior cruciate ligament attaches to the facet on the anterior part of the intercondylar area of the tibia and ascends posteriorly to attach to a facet at the back of the lateral wall of the intercondylar fossa of the femur. The Anterior cruciate ligament crosses lareral to the posterior cruciate ligament as they passes through the intercondylar region. The anterior cruciate ligament prevent the anterior dislocation of tibia relative to femur. It is tout during knee extension.

7. P osterior cruciate ligament Posterior cruciate ligament attaches to the posterior aspect of the intercondylar area of tibia and ascends anteriorly to attach to the medial wall of the intercondylar fossa of the femur. Posterior cruciate ligament resist posterior displacement. It touts during knee flexion.

8. M edial collateral ligament  or  T ibial collateral ligament A ttached proximally to the medial  epicondyle  of the femur immediately below the  adductor tubercle . B elow to the  medial condyle of the tibia  and medial surface of its body. It resists forces that would push the knee medially, which would otherwise produce  valgus deformity .

9. L ateral collateral ligament or Fibular collateral ligament   Fi bular collateral ligament stretches obliquely downward and backward. Fr om the  lateral epicondyle  of the  femur  above, to the  head of the fibula  below. Seperated from lateral Meniscus by Popliteal tendon and fibrous capsule. Tightest in extension,0 to 30degrees Becomes looser in flexion>30 degrees

10. Medial Meniscus It is relatively immobile It is C shaped/semilunar(Fibrocartilagenous disc) Peripheral margin adherent to tibial collateral ligament. More liable to injury.

11. Lateral Meniscus It is more round/circular in shape The posterior end of the Meniscus is attached to femur through two meniscofemoral ligament. The tendon of Popliteal and fibrous capsule separate it from Lateral collateral ligament. The mobility of posterior end is controlled by Popliteal and 2 meniscofemoral ligament.

12. Function of menisci Shock absorption Redistributes force Spread synovial fluids Minimal effect on stability On rotation menisci move with femur Lateral moves 20-24 mm Medial less mobile 10-15 mm Lateral menisci bear more load.

13. Oblique Popliteal ligament It is an extension from semimembranosus tendon close to its insertion to the tibia Oblique Popliteal ligament passes upward and laterally. It is attached above to the upper margin of the  intercondyloid fossa  and posterior surface of the  femur  close to the articular margins of the  condyles . B elow to the posterior margin of the head of the  tibia .

14. Arcuate Popliteal ligament  It is Y-shaped. attached to the posterior portion of the  head of the   fibula . From there it goes to its two insertions; the medial one goes over  popliteus muscle  and blends with the  oblique popliteal ligament , the lateral one to the  Lateral epicondyle  of the  femur  and blends there with the lateral head of  gastrocnemius muscle .

15. BURSAE As many as 13 bursae have been described around the knee joint Four are anterior Four are lateral Five are Medial

16. Anterior bursae These are four in numbers: Subcutaneous prepatellar bursae Subcutaneous infrapatellar bursae Deep infrapatellar bursae Suprapatellar bursae

17. Lateral burase There are four lateral bursae: A bursae deep to lateral head of gastrocnemius A burase between Fibular Collateral ligament and the biceps femoris. A burase between Fibular Collateral ligament and tendon of popliteus. A bursae between tendon of popliteus and lateral condyle of tibia.

18. Medial bursae There are Five medial bursae: A bursae deep to the medial head of gastrocnemius The Anserine burase A bursa deep to the Tibial collateral ligament. A bursae deep to semimembranosous. Occasionally a FIFTH bursae present between tendon of semimembranosous and Semitendinosus.

19. Relations of knee Anteriorly : Anterior bursa Ligamentum Patellae Patellar plexus

20. Posteriorly : Popliteal vessel Tibial nerve Peroneal nerve Gastrocnemious Plantaries Semimembranosous Semitendinosus Gracilis Popliteus

21. MEDIALLY : Sartorius Gracilis, Semitendinosus, Saphanous vain Saphanous nerve Semimembranous LATERALLY: Biceps Femoris Tendon of popliteus

22. Locking of knee It is the terminal stage of knee extension. The tibia is laterally rotated and femur is Medially rotated. This rotatory movement locks the joint(which means that the joint cannot be flexed unless it is unlocked by reverse rotation) In full extension with the locked knee,all the muscles are stretched and the joint is stable. Produced by biceps femoris muscles.

23. Unlocking of knee “ Unlocking” of knee.During knee flexion first it is necessary to “untwist” and reduce tension within the major ligament of knee joint. Contraction of popliteus muscles, Because of contraction of popliteus muscles, Femur laterally rotates on the tibia and pulls the lateral Meniscus posteriorly. Once the femur is laterally rotated the knee is said to be unlocked.

24. INVESTIGATION

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