Therapeutic Kinesiology:Musculoskeletal Systems, Palpation, and Body Mechanics

Therapeutic Kinesiology Instructor Manual: Ch12 p.7 TK INSTRUCTOR MANUAL: CHAPTER 12 The Knee Chapter manuals include: Objectives Lecture Notes Suggested Classroom and Student Development Activities For other chapter-by-chapter resources, see: Key Term Quizzes Muscle Origin and Insertion Worksheets Muscle OIAs List by Chapter MyTest Test Bank For additional resources see “Teaching Tips and Tools”: 7 research-based learning principles for kinesiology courses in massage 5-step self-directed learning cycle for body mechanics courses Tools that build metacognitive skills: e.g., concept (mind) maps, grading rubrics, and self-assessments inventories OBJECTIVES Name the three bones of the knee. List and demonstrate the palpation of 10 bony landmarks of the knee. Describe the menisci and bursae in the knee. Name and describe the two joints of the knee and seven supporting ligaments. Describe patellar movement and problems that occur with poor patellar tracking. Define the mechanical axis of the lower limb and the Q angle. Describe the range of motion and joint mechanics of the tibiofemoral joint. Name types of misalignments in the knee and describe the structural problems they cause. Define and contrast axial rotation and terminal rotation of the knee. Demonstrate the palpation of the menisci and prepatellar bursa of the knee. Identify the origins, insertions, and actions of the knee flexors and extensors. Identify the trigger points and pain referral patterns of the knee flexors and extensors. Demonstrate the active movement and palpation of the knee flexors and extensors. LECTURE NOTES BONES OF THE KNEE Largest and most complex joint in body Functional link between feet and hips Allows us to move torso closer to ground Paradox of knee Balancing vertical stability with extreme mobility Knees work under extreme compression stress Functions as a major shock absorber Most minimally congruent joint Result: most commonly injured joint Three bones of the knee Femur Longest bone in the body Bowed for flexibility Shaft and neck shaped like the number 7 Distal end flares into triangular shape Two large epicondyles on distal end Lateral condyle two times the size of medial condyle Tibia Massive, thick vertical shaft Transfers weight from knee to foot Tibial plateau on proximal end Horizontal surface for axial weight loading Patella Triangular-shaped sesamoid bone, kneecap Menisci: Fibrocartilage disks in knee Absorb shock Distribute load circumferentially across joint Reduce friction during motion Stabilize by improving joint congruency Guide pathway of motion Bursae: Fluid-filled synovial sacs around knee Approximately 14 bursae padding knee Functions: Reduce friction Located under tendons, between sliding structures Two types Free bursae Envaginations of synovial lining JOINTS AND LIGAMENTS OF THE KNEE Patellofemoral joint: Between patella and femoral intercondylar groove Serves as anatomical pulley Increases mechanical advantage of extensor muscles Protects tibiofemoral joint from tendinous friction Deflects pull of quadriceps away from femur Tibiofemoral joint: Between tibia and femur Both joints share large, fibrous joint capsule Both joints stabilized by multiple ligaments/tendons Ligaments are taut in knee Ligaments are slack in flexion to allow rotation Muscular tendons around knee provide backup support Lateral ligaments of knee Lateral collateral ligament (LCL): fibular collateral ligament Lateral epicondyle to head of fibula Prevents excessive abduction, genu varum (bowlegs) Medial collateral ligament (MCL): tibial collateral ligament Medial epicondyle to proximal tibia Prevents excessive aduction, genu valgus (knock-knees) Anterior cruciate ligament (ACL) Anterior tibia to posterior lateral femoral condyle Prevents anterior displacement of tibia Twists around PCL during flexion/extension Posterior cruciate ligament (PCL) Posterior tibia to medial femoral condyle Short, thicker, twice as strong as ACL Prevents posterior displacement of tibia Patellar ligament Blends into quadriceps tendon Short, flat ligaments over patella Secures front of knee Iliotibial band (ITB), also called iliotibial tract (ITT) Flat, broad tendon of tensor fascia latae Stabilizes lateral side of knee Oblique popliteal ligament Broad, flat posterior ligament covering capsule Tendinous expansion of semimembranosus muscle Common knee injuries Cruciate ligament rupture or tear Causes drawer sign: Excessive tibial displacement With ACL injury tibia will displace anteriorly With PCL injury tibia will displace posteriorly "Terrible triad" Common knee injury in contact sports. From posterior lateral blow to knee. Damages ACL, medial meniscus, and MCL Patellar motion and tracking Patella glides up/down intercondylar groove Patella tracks along curvilinear path Thick hyaline cartilage covers/protects posterior patella Patellar dysfunctions Patellofemoral pain syndrome From poor tracking from imbalanced muscle pulls Causes arthritis, inflammation, recurring dislocation Chondromalacia Reoccurring inflammation to hyaline cartilage Causes premature deterioration of patellar cartilage Restricts gliding motion, causes stiffness and pain Iliotibial band syndrome Inflammatory condition, common cause of knee pain Tight, fibrotic ITB rubs lateral femoral epicondyle Knee alignment Knee is highly calibrated joint Optimal knee alignment minimizes shock and wear Measures of knee alignment Mechanical axis of lower limb Q angle: average 15 degrees Normal genu valgum: 510 degrees Knee misalignment Genu varum A bow-legged alignment Increases compression on medial meniscus 5 degrees of genu varum increases disk compression by 50% Genu valgum A knock-kneed alignment Increases compression on lateral meniscus Range of motion in knee Flexion: soft end-feel 120 degrees with hip straight 140 degrees with hip flexed Extension: 5 degrees Hyperextension in knee Genu recurvatum Hyperextension of knee beyond normal range Occurs when stabilizing muscles fail Common in lordotickyphotic postures Rotation of knee Axial rotation: tibia rotates with knee in flexion 30 degrees medially 40 degrees laterally Rotation only occurs during flexion Terminal rotation: screw home mechanism Occurs at end of extension to stabilize knee Tibia and femur counterrotate, twist, and lock Movement of the menisci Femoral condyles press menisci across tibial plateau Lateral meniscus moves 12 millimeters, twice the distance of medial meniscus During flexion menisci move posteriorly During extension menisci move anteriorly During rotation menisci move opposite each other If disk shifts too slowly, tears can occur MUSCLES OF THE KNEE Overview of muscles of the knee Extensors: quadriceps Flexors: hamstrings Rotators: hamstrings, popliteus, gracilis, sartorius Dynamic stabilizer: gastrocnemius Flexors of knee: Quadriceps (Figure 12.40) Rectus femoris: Only two joint muscles in group O: Anterior inferior ischial spine (AIIS) I: Tibial tuberosity via patellar ligament A: Flexes hip and extends knee Vastus medialis: Distal oblique fibers stabilize patella Vastus intermedius: Lies deep to rectus femoris Vastus lateralis: Largest, most lateral vasti O: Lateralis – Lateral edge of linea aspera, gluteal tuberosity, greater trochanter Medialis – Medial edge of linea aspera Intermedius – Upper two-thirds of anterior and lateral femoral shaft I: Patellar ligament and tibial tuberosity A: Extends knee; vastus medialis oblique stabilizes the knee Extensors of knee: Hamstrings Biceps femoris: Only two joint muscles in group Semimembranosus: Attaches to medial meniscus via capsule O: Ischial tuberosity I: Posterior and medial aspect of medial tibial condyle A: Flexes knee and assists medial rotation, extends hip and assists medial rotation Semitendinosus: Tendon inserts on pes anserinus O: Ischial tuberosity I: Proximal part of medial tibia A: Flexes knee and assists medial rotation, extends hip and assists medial rotation Other muscles acting on knee Gastrocnemius: Dynamic stabilizer in knee extension Sartorius: "Tailor's muscle," assists knee flexion and medial rotation Gracilis: Assists flexion when hip is flexed Popliteus: Medial rotator of knee Unlocks knee from terminal rotation Tendon attaches to lateral meniscus SUGGESTED CLASSROOM STUDENT DEVELOPMENT ACTIVITIES PROVIDE AN OVERVIEW OF THE CLASS Before class, write a short schematic overview of the class on the board, then go over it at the beginning of class. For example: Today's class covers: Bones of knee Joints and ligaments Muscles of knee Activities: Review, lecture and assessments, palpation exercises, recap STRUCTURAL OBSERVATION EXERCISE: The knee Have three students volunteers stand next to each other so that the other students can observe their knees. Have the volunteers remove their shoes and socks and roll their pants up past their knees. Ask the students the following questions: Standing front view Look at knees in relation to neutral. Do you see genu valgum (knock-kneed) or genu varum (bow-legged) stresses? If so, how does this affect the alignment of the hips and ankles? Is VMO working? (If so, the kneecap will be lifted.) Is tibia relatively vertical or twisted? Which direction does the kneecap point? If it does not point straight ahead, what is causing it to point in another direction? (Could be coming from rotation in the hips, could be from torsion in the knee, could be from overpronation or supination in the foot or ankle.) What is the position of knee in neutral (chronic flexion or HE)? How does this affect muscles around the knee? How do torsions in knee affect chain of joints and muscles in LL? Look down to overpronation and oversupination. Standing side view Have the students turn sideways and look at the knee alignment. Are the knees straight, bent, or hypextended? Is the heel under or behind the ankle (the calcaneus should extend behind the ankle)? Check the relationship of the knees to the position of the pelvis (is it level or tilted?) and the spinal alignment. Have the students slightly bend the knees and notice what happens to the position of the pelvis and spinal alignment. Have the students hyperextend the knee and notice what happens to the position of the pelvis and the spinal alignment. Sitting Have the students sit on a massage table with the lower legs hanging off the sides. Look at how the tibia hangs. Is it vertical? Rotated? Abducted or adducted? Check rotations (3040 degrees in flexion). Movement observation* Have the students do a small knee bend and extension. Do the knees stay aligned with the hips and ankles in the sagittal plane during the knee bend? Is the knee moving over second toe? Check angle of inclination in femur (57 degrees is normal). Rotations/counterrotations of tibia and femur at joint. Flex: Tibia medially rotates, femur laterally rotates. Reverse on extension. What excessive rotations do you observe? With rotations, what muscle would be short and which stretch-weakened? *Note: See knee video segment for demonstration of tibiofemoral rotations in flexion and extension. PALPATION EXERCISES Bony landmarks of the knee (p. 336) Menisci and bursae in the knee (p. 339) Ligaments of the knee (p. 343) EXPLORING TECHNIQUE EXERCISES Passive range of motion for the knee (p. 352) Tibiofemoral rotations (p. 353) SELF-CARE EXERCISES Correcting genu recurvatum (hyperextended knees) (p. 350) Tracking and guiding menisci motion (p. 356) © 2013 by Education, Inc. Foster, Instructor Resources for Therapeutic Kinesiology