Bursae around knee joint

BRIEF ON KNEE

1. ANATOMY KNEE JOINT SUSHANT S. SONARKAR

2. KNEE JOINT It is the largest and most complicated joint in the body.

3. FUNCTIONS 1. Weight bearing. 2. Essential for daily activities: standing walking & climbing stairs. 3. The main joint responsible for sports: running, jumping , kicking etc.

4. ARTICULATING BONES 1. Lateral and medial articulations between the tibial condyles and their cartilaginous menisci and the corresponding femoral condyles.

5. ARTICULATING BONES 2. Intermediate articulation between the patella and femur.

6. THE FEMORAL CONDYLES The medial extends further forwards . The lateral is more oval. The condyles are convex from front to back.

7. TIBIAL CONDYLES ( PLATEAUS ) are flat . The medial is oval The lateral is round. The articular surfaces are covered with hyaline cartilage .

8. TYPE A synovial joint of the hinge variety between the medial and lateral condyles of the femur and the corresponding tibial condyles with some degree of rotation .

9. TYPE A synovial joint of the plane gliding variety between the patella and the patellar surface of the femur.

10. CAPSULE It is absent Anteriorly . It is Replaced by : Quadriceps femoris tendon. Patella . Ligamentum patellae .

11. CAPSULE Posteriorly : (a) Superior : Attached proximal to the articular margins of the femoral condyles and to the intercondylar fossa. It is deficient above the lateral condyle for the passage of tendon of popliteus .

12. CAPSULE (b) Inferior : Attached to the tibia EXCEPT when the tendon of Popliteus crosses the bone.

13. EXTRACAPSULAR LIGAMENTS 1. Ligamentum Patellae It is the inter mediate part of the tendon of quadriceps femoris .It is supported by the patellar retinaculi (expansions from the vasti) They strengthen the capsule on each side.

14. 2. TIBIAL (MEDIAL) COLLATERAL A flat band . Attachment: Above to the medial condyle of the femur . Below to the medial surface of the shaft of the tibia. Firmly attached to the medial meniscus .

15. 3. LATERAL (FIBULAR) COLLATERA Cord like. Attachment : Above : lateral condyle of the femur. Below : head of the fibula. Separated from the lateral meniscus by the tendon of popliteus .

16. 4. OBLIQUE POPLITEAL An expansion of the Semimembranosus . It strengthens the capsule posteriorly.

17. INTRA CAPSULAR STRUCTURES 1. CRUCIATE LIGAMENTS. 2. MENISCI. 3. TENDON OF POPLITEUS .

18. CRUCIATE LIGAMENTS They are the main bond between the femur and tibia throughout the joint ’ s movements. They Cross each other within the joint cavity. They are named Anterior and Posterior according to their tibial attachments.

19. ANTERIOR CRUCIATE Tibial attachment : Anterior intercondylar area. Course : Upward, backward and laterally. Femoral attachment: Posterior part of medial surface of the lateral condyle.

20. ANTERIOR CRUCIATE FUNCTION Prevent posterior displacement of the femur on the tibia and the tibia from being pulled anteriorly when the knee joint is flexed. It is taught in hyper extension .

21. POSTERIOR CRUCIATE Tibial attachment : posterior inter condylar area. Direction: upward, forward and medially. Femoral attachment: Anterior part of the lateral surface of the medial condyle.

22. POSTERIOR CRUCIATE Function : prevents anterior displacement of the femur on the tibia and the tibia from being pulled posteriorly when the knee joint is flexed. It is taught in hyper flexion.

23. MENISCI C shaped sheets of fibro cartilage. The peripheral border is thick and attached to the capsule. The inner border is thin and concave and forms a free edge.

24. MENISCI The upper concave surfaces are in contact with the femoral condyles. The lower flat surfaces are in contact with the tibial condyles.

25. MENISCI Functions : 1. Deepen the tibial articular surfaces. 2. Act as cushions between the two bones.

26. MEDIAL MENISCUS Crescentic in shape . More liable to injury due to its attachment to the medial collateral ligament and to the capsule. It is relatively immobile.

27. LATERAL MENISCUS More rounded in shape. Its anterior and posterior ends lie within the ends of the medial meniscus. Posteriorly it is separated from the fibular collateral ligament by the tendon of popliteus. Less liable to injury.

28. INJURY OF THE MENISCI The menisci are frequently injured especially in footballers and cricketers. The medial is torn three times more often than the lateral. The injury is produced by the rotation of the femur on the tibia or the reverse with the knee joint partially flexed and carries the weight of the body.

29. INJURY OF THE MENISCI The torn part of the meniscus is wedged between the tibial and femoral condyles. No further movement is allowed and the joint is kept locked .

30. SYNOVIAL MEMBRANE It lines the lateral and medial parts of the capsule. Anteriorly : It forms the supra patellar bursa . It is attached to the inter condylar area of the tibia and to the lateral and medial borders of the patella.

31. SYNOVIAL MEMBRANE It is reflected backward from the posterior surface of the ligamentum patellae to form the Infrapatellar fold. The free borders of the fold are the Alar folds . The space between these folds contains fat ( Infrapatellar pad of fat ).

32. SYNOVIAL MEMBRANE Posteriorly : It Passes out to surround the cruciate ligaments. It is continuous with the surface layer of the menisci. It covers the tendon of popliteus and forms a bursa around it ( popliteal bursa ). It forms the semimembranosus bursa .

33. ANTERIOR BURSAE They are four : 1. Suprapatellar : It is 3 fingerbreadths above the patella. Always continuous with the joint cavity. Held in position by the articularis genus muscle. Accumulation of fluid in the joint causes excees fluid in the bursa leading to floating patella.

34. ANTERIOR BURSAE 2. Prepatellar If enlarged it causes ( House Maid ’ s ) bursa.

35. ANTERIOR BURSAE 3.Superficial Infrapatellar . (PARSON ’ S bursa 4.Deep Infrapatellar .

36. POSTERIOR BURSAE (6) 1. POPLITEAL Always continuous with the joint cavity. 2. SEMIMEMBRANOSU Usually communicates with the joint cavity. 3 & 4. GASTROCNEMIUS Around sartorius,gracilis and semitendinosus.

37. MOVEMENTS 1. FLEXION Hamstrings ( supplied by the sciatic nerve). Assisted by sartorius, popliteus and gracilis. Checked by back of calf in contact with the back of the thigh.

38. MOVEMENTS 2. EXTENSION Quadriceps Femoris (supplied by the femoral nerve.) Limited by tension of the cruciate and collateral ligaments.

39. MOVEMENTS 3. ROTATION (A) MEDIAL: Sartorius, gracilis and semitendinosus . (B) LATERAL : Biceps femoris

40. NERVE SUPPLY Femoral. Obturator. Sciatic. Common peroneal. Tibial.

41. UNLOCKING At the commencement of Flexion of the extended knee. Aim : To slack the ligaments especially the cruciate. FEMUR : Lateral rotation (the foot is on the ground) TIBIA: Medial rotation. Muscle : POPLITEUS

42. LOCKING The joint assumes the position of full extension . It becomes a rigid structure. The menisci are compressed between the tibial and femoral condyles. Tightening of all the major ligaments. The femur is medially rotated on the tibia.

43. RELATIONS Anterior : Prepatellar bursa.

44. RELATIONS Posterior : Boundaries and contents of Popliteal Fossa . Medial : SGS muscles. Lateral : Biceps femoris and common peroneal nerve.

45. STABILITY 1. Muscles : QUADRICEPS particularly the inferior fibers of the vasti lateralis and medialis. Many sport injuries can be preventable through appropriate training and conditioning of the muscle.

46. STABILITY 2. Ligaments : The knee joint can function well following a ligamentous strain if the quadriceps is intact.

47. INJURY OF THE JOINT TRIAD OF INJURY 1. Medial collateral ligament. 2. Medial meniscus . 3. Anterior cruciate ligament. The joint becomes swollen because it is filled with blood ( hemarthrosis ).

48. ANTERIOR CRUCIATE INJURY Tear of the anterior cruciate ligament is more common than the posterior. The tibia can be pulled excessively forward on the femur

49. POSTERIOR CRUCIATE INJURY The tibia can be pulled excessively backward on the femur.

50. INJURY OF THE CRUCIATE LIGAMENTS Management : Knee is kept immobilized in slight flexion. Active physiotherapy of the quadriceps femoris at once. Operative repair (incase of torn of the capsule and collateral ligaments).