Radiological anatomy of Knee joint.pptx

Radiological anatomy of Knee joint , this is prepared by me for my presentation at department. if someone is benefitted that will be a great pleasure for me.

1. Radiological anatomy of The knee joint Presented by Capt Alauddin MD residency , phase A Dept of Radiology and Imaging, CMH, Dhaka.

2. Knee joint : Synovial hinge joint and the largest synovial joint in the body.

3. Articular surfaces : • The medial and lateral femoral and tibial condyles , • The medial tibial articular surface is larger • The femoral condyles have a groove at the junction of the patellar and tibial articular areas. Joint space ranging from 3 to 8 mm.

4. • The patellofemoral compartment is a saddle joint between the femoral trochlea and patella, formed by a large steeper lateral facet and two smaller medial facets.

5. Imaging modalities for Knee joint: Plain X ray USG CT scan MRI Arthrography

6. Plain X ray: Routine imaging includes AP view Semiflexed lateral view Tunnel view Skyline view

7. Tunnel view Skyline view

8. P lain x ray knee joint: Subcutaneous and intra- articular fat outlines some of the soft tissues around the joint. The ligamentum patellae is visible this way.

9. USG of the knee   : high-resolution imaging of superficial knee anatomy And evaluation of some of the tendons and ligaments. However cruciate ligaments and the menisci are usually difficult to visualize.

10. Indications of USG of knee: Baker’s cyst Bursitis Joint effusions Parameniscal cysts etc

11. MRI of knee joint: MRI is used in the evaluation of internal derangements of the knee using a dedicated quadrature surface coil images are acquired in the coronal plane to evaluate the collateral and cruciate ligaments, in the sagittal oblique plane to evaluate the cruciates and menisci, and in the axial plane to evaluate patellofemoral cartilage .

12. For better understanding mri we need to know some relevant mri anatomy , such as Fibrous capsule : Attached to the margin of the articular surfaces . • It is partly deficient superiorly, where the joint cavity communicates with the suprapatellar bursa, and posteriorly , where it may allow communication with the semimembranosus and popliteal bursa. • The capsule includes the tibial tuberosity and fibular head and is pierced by popliteus tendon posteriorly .

13. Synovium : • The synovium lines most of the capsule and extends into the suprapatellar bursa. • The infrapatellar bursa separates the synovium from the patellar tendon • Posteriorly , an anterior synovium reflection from the capsule covers the front and sides of the cruciate ligaments, rendering them intracapsular but extrasynovial . • The menisci are not covered by synovium . sinovium

14. Menisci : • Tibial concave articular surface is partially covered by two semilunar fibrocartilages , called menisci, which distribute weight-bearing stresses through the joint surfaces and improve stability. • The menisci in cross section are triangular . • Menisci are poorly vascularized with only partial blood supply from the external surface, hence they heal poorly following trauma. • The medial meniscus is larger, more semicircular and thickest posteriorly . • The lateral menisci is smaller, thicker and forms a nearly complete ring.

15. A discoid meniscus refers to a meniscus, almost always the lateral one, that is not C-shaped but disklike . it covers most of the tibial plateau to varying degrees rather than just its periphery. is usually seen in children and adolescents, in whom it may be asymptomatic and noted incidentally. It is prone to tearing

16. Meniscal attachments • The meniscofemoral ligament, from the posterior horn of the lateral meniscus to the medial femoral condyle , It is divided by the posterior cruciate ligament into the ligaments of Humphrey anteriorly and ligament of Wrisberg posteriorly .

17. • The external aspect of the medial meniscus blends with the capsule and medial collateral ligament • Popliteus tendon blends with the lateral meniscus and separates it from the lateral collateral ligament. • Transverse ligament joins the anterior horns of the menisci.

18. Popliteus contraction during flexion pulls the posterior horn of the lateral meniscus posteriorly allowing external rotation of the femur to unlock the extended knee.

19. Meniscal tear: Following repetitive trauma, as part of the ageing process the central portion of the meniscus undergoes degeneration Such changes are classified as intrasubstance focal signal change (slight T 1 and T 2 hyperintensity ) is classified as grade 1 linear or diffuse globular signal abnormality not extending to a surface is classified as grade 2, signal abnormality, either linear or globular with definite extension to a surface, is classifi ed as grade 3

20. The anterior cruciate ligament (ACL) : arises from the medial part of the anterior intercondylar area of the tibia and passes upwards, laterally and posteriorly to attach to the posterior part of the medial aspect of the lateral femoral condyle . On MR images, the anteromedial bundle (AMB) and a more vertical posterolateral bundle (PLB ) are clearly defined as they are surrounded by higher-signal connective tissue .

21. The posterior cruciate ligament (PCL) : Attaches to the posterior intercondylar area of the tibia and passes upwards, medially and anteriorly to attach to the anterior part of the lateral aspect of the medial femoral condyle . The PCL is stronger than the ACL PCL is also formed by two bundles anterolateral and posteromedial . PCL is intensely hypointense on MR,

22. The medial collateral ligament: Composed of deep fibres intimately related to the meniscotibial and meniscofemoral ligaments, and to the joint capsule.

23. The lateral collateral ligament complex : composed of three layers; outer layer is formed by iliotibial band anteriorly and the biceps femoris tendon posteriorly , cord-like fibular collateral ligament forms the middle layer and the deep layer is formed by the popliteus tendon.

24. Arthrography  of the knee joint   : Contrast medium and air are introduced into the joint deep to the patella and allow visualization of the synovial cavity of the joint including the suprapatellar bursa and some or all of the associated bursae that may be connected with the joint cavit . The menisci are seen as filling defects, triangular in cross section , whose upper and lower surfaces are outlined by contrast .