The Knee Clarification of Terms The knee consists of: The tibiofemoral joint Patellofemoral joint Mansfield, p273 Osteology of the Knee Distal Femur Proximal tibia and fibula Patella 1
Osteology of the Knee Distal femur (ADDuctor tubercle) Right Femur Osteology of the Knee The proximal tibia & fibula The medial and lateral condyles of the tibia form the shallow articulations with the distal femur Fibular Head Tibial Tuberosity The intercondylar/intercondyloid eminence the attachment point for the cruciate ligaments Interosseous Membrane Osteology of the Knee Patella 2
What can you palpate? What can you NOT palpate? Joint Structure Tibiofemoral Joint Articulation between the large condyles of the distal femur and the relatively flat proximal tibia Patellofemoral Joint Articulation between the patella and distal femur Mansfield, p273 Joint Structure: Alignment Genu valgum refers to a frontal deviation of the position of the knee. Commonly referred to as knock-knee due to the distal segments being positioned more laterally than normal Genu varum refers to a frontal deviation of the position of the knee. Commonly referred to as bow-leg is the opposite. Lippert, p294 & Mansfield, p278 3
Joint Structure: Alignment Genurecurvatum: Hyperextension of the tibiofemoral joint placing excessive stress on the structures in the popliteal space Tibial nerve Popliteal Vein Popliteal Artery Common Peroneal Nerve Joint Structure: Alignment Q Angle * angle between the quadriceps muscle and the patellar tendon * draw a line from the ASIS to the midpoint of the patella and from the tibial tuberosity to the midpoint of the patella * tends to be greater in females due to wider pelvis Lippert, p285 Joint Movement Tibiofemoral Joint: Osteokinematics: flexion, extension Arthrokinematics: Open chain = Closed chain = (hint: convex distal femoral condyles and concave proximal tibial plateau) Lippert, p284 & Mansfield, p284 4
Joint Movement Patellofemoral Joint Osteokinematics n/a Arthrokinematics The smooth posterior surface of the patella glides over the femur It glides and tilts in all 4 directions Lippert, p285 Supporting Structures ACL & PCL (Sagittal plane stability) MCL & LCL (Frontal Plane stability) Posterior capsule Medial and lateral menisci Supporting Structures Anterior Cruciate Ligament (ACL) Keeps femur from moving posteriorly on tibia and from tibia from moving anteriorly on femur Tightens during extension, preventing hyperextension Posterior Cruciate Ligament (PCL) Keeps femur from moving anteriorly on tibia and from tibia from moving posteriorly on femur Tightens during flexion Lippert, p288 5
Supporting Structures: ACL & PCL Supporting Structures Medial Collateral Ligament (MCL) Lateral Collateral Ligament (LCL) Flat broad ligament attaching the medial condyles of femur and tibia It protects the joint from stresses to the side of the knee. Round, cordlike ligament attaching from lateral femoral condyle to fibular head It protects the joint from stresses to side of the knee. Lippert, p288 Supporting Structures: MCL & LCL 6
Supporting Structures Posterior Capsule: Prevents hyperextension of the knee Mansfield, p282 Supporting Structures Lippert, p288 Medial and lateral menisci Two half-moon, wedge-shaped fibrocartilage disks Located on the superior surface of the tibia Designed to absorb shock Thicker laterally than medially Proximal surfaces are concave, deepening the relatively flat joint surface of the tibia Knee Structure Popliteal Space Area behind the knee containing important nerves (tibial and common peroneal) and blood vessels (popliteal artery and vein) Diamond shaped fossa Bound superiorly by semitendinosus and semimembranosus on the medial side and biceps femoris on lateral side. Bound inferiorly by the medial and lateral heads of the gastrocnemius Lippert, p288 7
Myology Muscles of the Knee Area Mono-articular Muscle Bi-articular Muscle Anterior Vastus Lateralis Rectus Femoris Posterior Medial Vastus Medialis Vastus Intermedialis Biceps femoris (short) Popliteus Biceps femoris (long) Semimembranosus Semitendinosus Gastrocnemius Sartorius Gracilis Lateral Tensor Fascia Latae Lippert, p290 Your subtopic goes here Rectus Femoris Innervation Femoral n. tidbit Anterior-inferior iliac spine Tibial tuberosity via the quadriceps tendon Hip flexion, knee extension One of the heads of the quads Lippert, p291 Vastus Medialis linea aspera Innervation Femoral n. tidbit Tibial tuberosity via the patellar tendon Knee extension One of the heads of the quad VMO one of the first muscles of the knee to atrophy post-operatively, responsible for last 10-15 o of knee extension Vastus Medialis Obliquus Lippert, p291 8
Vastus Lateralis Linea aspera, Innervation Femoral n. tidbit Tibial tuberosity via the patellar tendon Knee extension Part of the quads Lippert, p291 Vastus Intermedialis Upper 2/3 of the anterior femoral shaft Tibial tuberosity via the patellar tendon Innervation Femoral n. Knee extension intermedialis Lippert, p291 Your subtopic goes here Biceps Femoris Ischial tuberosity Head of the fibula Innervation Tibial portion of the sciatic n. tidbit Hip extension, knee flexion One of the hamstrings A B C D A Bicep F Bicep F Semimem Semiten Lippert, 292 9
Your subtopic goes here Semimembranosus Ischial tuberosity Medial condyle of the tibia, posterior aspect Innervation Tibial portion of the sciatic n. Hip extension, knee flexion tidbit One of the hamstrings Lippert, p291 Your subtopic goes here Semitendinosus Ischial tuberosity Proximal-medial surface of the tibia (pes anserinus) Innervation Tibial portion of the sciatic n. Hip extension, knee flexion, tidbit One of the hamstrings Lippert, 292 Popliteus Innervation Tibial n. Posterior aspect of the lateral femoral condyle Posterior surface of the proximal tibia Initiates knee flexion Lippert, 292 10
Gastrocnemius Innervation Tibial n. Medial head: posterior aspect of the medial femoral condyle Lateral head: posterior aspect of the lateral femoral condyle Calcaneal tuberosity via the Achilles tendon Flexion of the knee, plantar flexion, Lippert, 293 Your subtopic goes here Sartorius ASIS Innervation Femoral n. tidbit Proximal-medial surface of the tibia (via the pes anserinus) Hip flexion, hip ABD, Hip ER, knee flexion Longest muscle in the body Biel, p326 Your subtopic goes here Gracillis Innervation Obturator n. Body and inferior ramus of the pubis Proximal-medial aspect of the tibia (pes anserinus) Hip ADD, hip flexion, knee flexion Biel, p321 11
Tensor Fascia Latae Iliac crest, posterior to ASIS Innervation Iliotibial tract Superior Gluteal Nerve Hip flexion, ABD, internal rotation Biel, p324 Myology Prime Movers of the Knee: Extension: Quadriceps group Flexion: Hamstring group Popliteus gastrocnemius Lippert, p294 Myology Summary of Muscle Innervation: Muscle Nerve Rectus femoris Femoral Vastus lateralis Femoral Vastus intermedialis Femoral Vastus medialis Femoral Semimembranosus Sciatic Semitendinosus Sciatic Biceps femoris long head Sciatic Biceps femoris short head Common Peroneal Popliteus Tibial gastrocnemius Tibial Lippert, p295 12
Common Knee Pathology Genu Valgum Genu Varum Genu Recurvatum Patellar Tendonitis Osgood-Schlatter Disease Patellofemoral Pain Syndrome Chondromalacia Patella Unhappy Triad Genu Valgum and Varum Lippert, p294 Genu Recurvatum Lippert, p294 13
Osgood-Schlatter Lippert, p294 Chondromalacia Patella Lippert, p294 Unhappy Triad Lippert, p294 14
Pin the Tail on the Donkey Point to the location of the Knee extensors Knee flexors References Biel, A., (2010). Trail Guide to the Body, 4 th ed. Boulder, CO: Books of Discovery. Lippert, L.S. (2011). Clinical Kinesiology and Anatomy, 5 th ed. Philadelphia, PA: F.A. Davis. Mansfield, P.J., & Neumann, D.A. (2009). Essentials of Kinesiology for the Physical Therapist Assistant. St. Louis, MO: Mosby Elsevier. 15