1. The Knee Joint

2. Classification of the joint
Modified hinge-type synovial joint
Motions
Flexion/Extension
Some internal/external rotation – primarily during knee flexion

3. Articulating surfaces of the knee
Femur
Large curved condyles covered with smooth hyaline cartilage with a gap in between – intercondylar notch

4. Patella Anterior surface covered by part of quadriceps tendon
Tendon forms the superficial part of the patellar ligament

5. Patella Posterior surface Medial facet Lateral facet
Articulates with the patellar articulating surface of the medial condyle of the femur
Odd facet
Lateral facet
Articulates with the patellar articulating surface of the lateral condyle of the femur
Non-articulating area
Distal to the pole or apex where the patellar ligament attaches
Fat pad of knee joint is deep to the distal pole of the patella

7. Borders of Patella
Superior
Medial
Lateral
Inferior – Apex of patella

8. The Tibia Superior Articular Surface Medial facet (medial condyle)
Shape:
Articulates with:
Meniscus –

9. Tibia pic
Medial side

10. Lateral facet
Shape:
Articulates with:
Meniscus:

11. Intercondylar eminence
Separates the medial and lateral facets of the tibia
Prevents:

12. Intercondylar areas Anterior intercondylar area
Attachment:
Posterior intercondylar area

14. Other parts of the tibia
Tibial tuberosity
Medial epicondyle
Posterior groove
Medial surface

15. Lateral epicondyle Lateral surface Posterior surface
Articular facet for fibula
Not part of the knee joint
Non-articular surface

16. Lateral tibial epicondyle cont.
Non-articular surface
Popliteus muscle crosses this surface
The muscle travels deep to the fibular collateral ligament

17. More knee joint General movements Articular capsule of the knee joint
Patellar ligament
LCL and MCL
Other ligaments of knee joint
Bursae
ACL and PCL
Menisci
Blood and nerve supply to the knee joint

18. Movements of the knee joint
Flexion
Limits:
Effects of skin
Rotation
Greatest during:

19. Extension Limits: Full extension Unlocking the knee
Tibial rotation in open chain
Femoral rotation in closed chain
Unlocking the knee

20. Articular capsule of the knee joint
Attachments of the joint capsule
Superiorly

21. Inferiorly
The capsule is prolonged inferolaterally over the popliteus muscle to the head of the fibular forming the arcuate popliteal ligament

22. Ligaments of the joint capsule
5 intrinsic (at least in part) ligaments that are external and strengthen and supplement the joint capsule
Patellar ligament
Fibular collateral ligament
Tibial collateral ligament
Oblique popliteal ligament
Arcuate popliteal ligament

23. Patellar ligament Strong thick band (though thin in some people)
Continuation of the:
Relation to the joint capsule
Infrapatellar fat pad:
Deep infrapatellar bursa
Patella – sesamoid bone

24. Fibular Collateral Ligament
AKA: Lateral collateral ligament
Dimensions
Length
Attachments

25. FCL (LCL) The tendon of the biceps femoris is split in two by the LCL
To locate the inferior attachment, follow the tendon of the biceps femoris muscle
FCL separated from the joint capsule inferiorly by fatty tissue
Tendon of popliteus muscle passes deep to the FCL, separating it from the lateral meniscus (see next picture)

27. Superiorly the FCL is fused with the fibrous joint capsule of the knee joint, and this part is considered to be an intrinsic ligament

28. Tibial (Medial) collateral ligament
Dimensions
Length

29. MCL Attachments
Proximal
Distal

30. Deep fibers of the MCL attached to the:
Injury to the MCL is frequently associated with injury to the medial meniscus and the ACL
Blow to lateral knee
Bursa in MCL which is of clinical significance during post-MCL sprain recovery

31. Stress on fibers
Because the MCL is wide, the fibers can be stressed during knee movement
Anterior fibers stressed during:
Posterior fibers stressed during:

32. Oblique Popliteal Ligament
Posterior medial ligament
Extension of semimembranosus tendon
Travels superolateral to insert into central part of capsule
Strengthens posterior capsule

33. Arcuate popliteal ligament
Posterior lateral ligament
Arises from posterior part of head of fibula
Travels superomedial over tendon of popliteus muscle to attach to intercondylar area of tibia and lateral epicondyle of femur

34. Synovial capsule and bursae of the knee
Synovial capsule lines the fibrous joint capsule
Synovial capsule attaches to the:
The synovial cavity of the knee is the largest one in the body

35. Note that the synovial capsule is reflected around the cruciate ligaments

36. Bursae
Sacs lined with synovial membrane and filled with synovial fluid
May connect with the synovial cavity of a joint
Function:

37. Four bursae communicate with the synovial cavity of the knee joint
They lie deep to the tendons of the:
Quadriceps femoris muscles (suprapatellar bursa)
Popliteus muscle (popliteus bursa)
Gastrocnemius muscle
Semimembranosus muscle

38. Suprapatellar bursa Superior extension of synovial capsule Between:
Extends superior to base of patella
Permits free movement of muscle over distal femur: allowing for full flexion/extension
Held in place:

39. fig
Suprapatellar bursa

40. Popliteus bursa
Between tendon of the popliteus muscle and the lateral condyle of the tibia
Opens into lateral part of synovial cavity inferior to the lateral meniscus

41. Gastrocnemius bursa Extension of synovial cavity
Lies deep to attachment of the medial and lateral heads of the gastrocnemius muscle, separating the tendon from the femur

42. Semimembranosus bursa
Frequently a prolongation of the gastrocnemius bursa
Separates:
Communicates with the joint cavity
Location of the popliteal or Baker’s cysts

43. Bursae which do not communicate with the synovial cavity
Anserine bursa
Complicated structure with many sacs or pouches (diverticula)
Separates the common tendon
from the proximal part of the medial tibia and MCL

44. Anserine bursa

45. Subcutaneous prepatellar bursa
Location
Allows
Disorder
Subcutaneous infrapatellar bursa
Withstands pressure during

46. Deep infrapatellar bursa
Location
Separated from knee joint by the infrapatellar fatpad
Infrapatellar fatpad

47. bursa

48. Cruciate ligaments of the knee joint
Very strong ligaments located within the fibrous joint capsule of the knee
They are NOT within the synovial cavity of the knee
Rounded ligaments
Located between the medial and lateral femoral condyles
The ACL and PCL cross each other in an oblique orientation

49. Anterior Cruciate Ligament
Attachments
On tibia
Travels superiorly, posteriorly and laterally
On femur

51. ACL
Relatively slack during:
Relatively taut :
Prevents

52. Posterior Cruciate Ligament
Stronger than ACL
Attachments
On tibia:
Travels superiorly and anteriorly on the medial side of the ACL
On femur

53. PCL pic

54. PCL strain increases:
Strain relatively decreases:
Posterior meniscofemoral ligament

55. Prevents Main stabilizer of femur in the flexed knee
Walking downhill, downstairs

56. Menisci Crescent or wedge-shaped fibrocartilaginous structures
Attached to:
Coronary ligaments :
Transverse ligament of the knee:

57. Menisci pic

58. Function
The tibial condyles are flat or slightly curved.

59. Blood supply to the menisci
Periphery:
Arteries
Inner edge

60. Medial meniscus Broader posteriorly than anteriorly
Anterior attachment
Anterior intercondylar area of tibia
Anterior to attachment of ACL
Posterior attachment
Posterior intercondylar area of tibia
Anterior to attachment of PCL

61. Mobility of Medial Meniscus
Less mobile than Lateral meniscus
Firmly attached to deep surface of the tibial collateral ligament
Attachment sites are separated from each other
How would this affect mobility

62. The Lateral Meniscus Smaller than medial meniscus More freely movable
Though it covers a larger articular surface area of the tibia
More freely movable
Tendon of popliteus muscle
Attachment sites are attached closely together on the tibia
Posterior meniscofemoral ligament:

63. Blood supply to the knee joint
Middle genicular artery and the medial and lateral branches of the inferior genicular artery (branches of the popliteal artery)
Pierces the fibrous joint capsule and supplies

64. Nerve Supply to the Knee Joint
Articular nerves are branches of the:
Obturator nerve
Femoral nerve
Tibial nerve
Common Fibular (Peroneal) Nerve

65. Special Region of the Knee Popliteal Fossa
Diamond-shaped region posterior to the knee joint
Posterior to:
Distal 1/3rd of femur
Knee joint
Proximal tibia

66. Borders of the popliteal fossa
Superomedial
Superolateral
Inferomedial
Inferolateral

67. Walls of the popliteal fossa
Posterior part of fossa
Superficial popliteal fascia
Deep popliteal fascia
Floor of fossa

68. Superficial popliteal fascia
Contains
Fat
Vein –
3 nerves
Posterior femoral cutaneous nerve
Medial sural nerve
Lateral sural nerve

69. Deep popliteal fascia Strong, dense sheet of deep fascia
Protects deep neurovascular structures passing from thigh to leg
Pierced by small saphenous vein

70. Floor of popliteal fossa
Popliteal surface of femur
Fascia of popliteus muscle
Oblique popliteal ligament (medially)

71. Contents of popliteal fossa
Popliteal artery
Popliteal vein
Nerves – branches off the sciatic nerve

72. Popliteal Artery
Continuation of the femoral artery after it passes through the adductor hiatus
Branches
Medial superior genicular aa. (VL and femur)
Lateral superior genicular aa. (VM and femur)
Middle genicular aa. (menisci and cruciates
Medial and lateral inferior genicular aa. (menisci and cruciates)
Muscular branches to hamstrings, gastrocnemius, soleus and plantaris muscles

73. Popliteal Vein
Ascends from medial side of popliteal artery to the lateral side
Ends at the adductor hiatus where it becomes the femoral vein

74. Nerves in the popliteal fossa
Sciatic nerve

75. Tibial Nerve Genicular nerves Muscular branches
Follow branches of genicular arteries
Muscular branches
Popliteus, gastrocnemius, plantaris and soleus muscles
Medial sural cutaneous nerve
Between heads of gastrocnemius muscle

76. Common fibular nerve Follows:
Divides into superficial and deep fibular nerves in the leg
Most commonly injured nerve in the lower extremity
Lateral sural cutaneous nerve

77. Sural cutaneous nerve
Formed from medial and lateral sural cutaneous nerves
What does sural mean?

78. Injury to common fibular nerve

79. Injury to tibial nerve