Knee Anatomy Principles of Orthopaedics and Trauma Care

Knee Anatomy Principles of Orthopaedics and Trauma Care module January 2009 Alison Holman

The knee joint • Complex • Large • Comprises how many joints ? • Joint Biomechanics are very important

Surface Anatomy • Using the resource of www. an@tomy. tv, on the next slide, please label the structures : A, B & C. • Self examine or practice on a colleague to locate these structures, - Look - Feel - Move

Surface anatomy of the knee B A C

The Knee has 3 Joints • Lateral Tibio-femoral joint - between the lateral femoral condyle, lateral meniscus & lateral condyle of the tibia • Medial Tibio-femoral joint - between the medial femoral condyle, medial meniscus & medial condyle of the tibia • Patello-femoral joint - between the patella and the patello-femoral surface

Clinical Application • Examine the picture on the next page and work out, Ø how the tibia is likely to connect ? Ø at what angle (varus or valgus) ? Ø the implications for joint disease ? * A line has been drawn in green to suggest the line of the tibia.

Hip / knee alignment

Extra Capsular Ligaments • Comprise a sheath of ligaments surrounding the joint consisting mostly of muscle tendons or their expansions. • The most obvious of these to the eye and on examination are the fused tendons of the Quadriceps Femoris. • The power of the quadriceps musculature is important in the stability of the knee. Ø Name the 4 muscles of the quadriceps complex & their origins

Ligaments that strengthen & support the knee joint • Patella Ligament • Medial & lateral Patellar Retinacula • Oblique Popliteal Ligament • Arcuate Popliteal Ligament • Medial Collateral Ligament • Lateral Collateral Ligament

Application to practice • Using an@tomy. tv, label the identified structures on the next sheets. • Then consider the ligament structures, their function & associated injuries you may have encountered. or from the media & SPORTING HEROES …?

Knee, Anterior view (Knee close up, layer 11) B C A

Knee, Posterior view (Knee close up, layer 10) A B

Knee, medial aspect (Knee close up, layer 11) ?

Knee, lateral aspect (Knee close up, layer 11) ?

Intra Articular Ligaments • Cruciate Ligaments from the word ‘ cross’ • Anterior Cruciate Ligament (ACL), extends posteriorally & laterally from the area in front of the intercondylar eminence of the tibia, to the posterior part of the medial surface of the lateral femoral condyle. • It resists forward movement of the femur on the tibia • Label the Anterior Cruciate & related Ligament and any other interesting structures!

Anterior knee (Knee close up, layer 6) B C A

Posterior Cruciate Ligament (PCL) • It extends anteriorly & medially from a depression of the posterior medial intercondylar area and the lateral meniscus to the anterior part of the femoral medial condyle. • It resists backward displacement of the tibia • Label the Posterior Cruciate & related Ligaments

Knee – posterior view (knee close up, layer 6) A B

Bursae ! • Exercise: What is the function of the bursae … ? • Name 4 important bursae

Menisci Structure : • 2 Fibrocartilage discs • Poor vascular supply • Circumferential and radial fibres • Semi-lunar shape, triangular in cross section, peripherally attached to the tibial plateau

Tibial Plateau & Menisci ? ?

Menisci Function : • Deepens tibial plateau • Joint stabiliser • Transmits 50% of the compressive load in extension • Transmits 85% of the compressive load in 90 degree flexion

Nerve Supply : • derives from sciatic nerve which divides into Tibial & Common Peroneal nerve • dermatomes - L 1 - L 5 supply front of the thigh, medial/lateral leg areas & sole of foot. Blood Supply : • derives from External Iliac artery, becoming the Femoral artery then the Popliteal artery • Venous drainage from External Iliac vein becoming the Femoral vein, then the Popliteal vein + also from the Right Saphenous vein

Knee Joint Movement & Muscles • Flexion, - by hamstrings assisted by gracilis, gastrocnemius & sartorius • Extension, - by quadriceps femoris • Medial rotation, - by popliteus

The knee joint References: • An@tomy. tv