1 / 29

KNEE

KNEE. Tibiofemoral Joint. Modified hinge joint. Articulating surfaces: Femoral condyles: Convex and asymmetric. Medial condyle is larger than the lateral. Condyles are separated anteriorly by patellar groove. Condyles are separated posteriorly by intercondylar fossa.

kiara
Download Presentation

KNEE

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. KNEE

  2. Tibiofemoral Joint • Modified hinge joint. • Articulating surfaces: Femoral condyles: Convex and asymmetric. Medial condyle is larger than the lateral. Condyles are separated anteriorly by patellar groove. Condyles are separated posteriorly by intercondylar fossa.

  3. Tibiofemoral Joint • Articulating surfaces: Tibial plateaus: Concave and asymmetric. Articular surface of medial plateau is 50% larger than that of lateral. Separated by intercondylar tubercles.

  4. Menisci • Wedge-shaped fibrocartilage discs. • Ends of menisci = horns: Attached to intercondylar tubercles. • Coronary ligaments: Attach menisci to rims of plateaus. • Anterior transverse ligament: Joins menisci and allows them to move together.

  5. Menisci • Medial meniscus: Larger of the two. More securely attached. Also attached to medial collateral ligament and to semimembranosus muscle. More often injured than lateral.

  6. Menisci • Lateral meniscus: Attached to posterior cruciate ligament: Via meniscofemoral ligament. Attached to popliteus muscle.

  7. Menisci • Functions: Enhance stability of knee: Deepen articular surfaces. Distribute weight. Reduce friction between articular surfaces.

  8. Menisci • Movement: Medial meniscus moves posteriorly during flexion: Due to tension in semimembranosus muscle. Medial meniscus drawn forward during extension: Due to tension in anterior capsular fibers.

  9. Menisci • Movement: Lateral meniscus moves posteriorly during flexion: Drawn by tension in popliteal expansion. Distorts more than medial meniscus.

  10. Joint Capsule • Large and lax. • Deficient on lateral condyle: For passage of popliteal tendon. • Anterior wall replaced by quadriceps tendon. • Excludes cruciate ligaments. • Commonly communicates with synovial bursae.

  11. Bursae • Suprapatellar: Upward expansion of synovial cavity between femur and quadriceps muscle and tendon. Proximally receives insertion of articularis genus muscle.

  12. Bursae • Prepatellar: Lies between superficial surface of patella and skin. • Deep Infrapatellar: Lies between patellar ligament and tibia.

  13. Bursae • Subpopliteal. • Gastrocnemius: Under medial head of gastrocnemius.

  14. Bursae • Anserine bursa: Between pes anserinus and tibial collateral ligament. Note: pes anserinus = combined tendons of semitendinosus, gracilis, and sartorius.

  15. Ligaments • Collaterals: Medial (tibial): Attachments: Medial femoral condyle. Proximal tibia. Partly continuous with adductor magnus tendon. Attached to medial meniscus. Distally separated from tibia by genicular vessels and nerves.

  16. Ligaments • Collaterals: Lateral (fibular): Splits tendon of biceps femoris muscle. Separated from lateral meniscus by popliteal tendon.

  17. Ligaments • Anterior cruciate: Weakest of cruciates. Slack during flexion and taut during extension. Prevents backward sliding of femur on tibia. Prevents hyperextension of knee.

  18. Ligaments • Posterior cruciate: Taut during flexion and slack during extension. Prevents forward sliding of femur on tibia. Prevents hyperflexion of knee.

  19. Movements • Flexion: First part (0 to 25 degrees): Posterior rolling and spinning. Anterior sliding of femoral condyles on tibial plateaus. • Extension: First part: Femoral condyles roll anteriorly and slide posteriorly. Followed by rolling and spinning of condyles.

  20. Movements • Lateral-medial rotation of tibia: At 90 degrees of knee flexion: Up to 40 degrees of lateral rotation. Up to 30 degrees of medial rotation. Greater than 90 degrees of flexion: Medial and lateral rotation ROM decreases.

  21. Locking at Full Extension • During final few degrees of extension: Femur rotates medially on tibia. (Note that tibia would also rotate laterally on femur.) Knee is brought into close-packed position: Tibial tubercles are lodged in intercondylar notch. Menisci are tightly interposed between tibial and femoral condyles. = Locked or screw-home mechanism. • Popliteus laterally rotates femur for unlocking at beginning of knee flexion.

  22. Axes • Mechanical axis: From head of femur to head of talus. Almost equivalent to anatomic axis of tibia. • Anatomic axis: Extends along femoral shaft.

  23. Axes • Physiologic valgus: Normal angle at knee where femoral and tibial axes meet: 170 – 175 degrees.

  24. Axes • Genu valgum: Lateral deviation of tibia. Less than 170 degrees. Results in “knock knees.”

  25. Axes • Genu varum: Medial deviation of tibia. Greater than 170 degrees. Results in “bow legs.”

  26. Patellofemoral Joint • During knee flexion/extension: Central ridge of patella slides along central groove of femur.

  27. Patellofemoral Joint • During flexion: Tibia moves posteriorly. Ligamentum patellae pulls patella distally and posteriorly: Causes patella to remain firmly in apposition to femur.

  28. Patellofemoral Joint • During extension: Patella is pulled proximally by quadriceps. Vastus lateralis tends to pull patella laterally. Vastus medialis oblique counteracts vastus lateralis.

  29. Patellofemoral Joint • Q-angle: Formed by vector of quadriceps: From ASIS to middle of patella. And vector of pull of ligamentum patellae: From tibial tubercle to middle of patella. 15 degrees.

More Related