Chapter 1: Functional Anatomy and Biomechanics - Knee Region

Card Set Information

Chapter 1: Functional Anatomy and Biomechanics - Knee Region
2015-03-08 19:17:36
Knee Region
NPTE: Chapter 1
Show Answers:

  1. Knee Region: Femur
    • Femoral condyles convex in ant/post and med/lat planes
    • Lateral femoral condyle = longer surface area
    • Med femoral condyle descends further inferiorly
  2. Knee Region: Tibia
    • Medial tibial condyle = biconcave, large surface area, more stable (less mobile) 
    • Lateral tibial condyle = convex ant/post and concave med/lat, smaller surface area, less stable (more mobile)
  3. Patella
    • Vertical ridge divides medial and lateral parts
    • 2 horizontal ridges divide its 2 facets (med and lat)
  4. Knee Region Capsules
    • Tibiofemoral Capsule: distal femur and prox tib attachment
    • Prox Tibfib Joint: has fibrous capsule
  5. MCL
    • Medial aspect of med femoral condyle --> upper end of tibia
    • Post fibers blend with capsule
    • Runs oblique ant and info
    • Taught with ext, slackened with flex
    • Prevents ER and provides stability against valgus force
  6. LCL
    • Lat femoral condyle --> head of fibula
    • Runs obliquely inf and post
    • Taught with ext, slackened with flex
    • Prevents ER and provides stability against varus force
  7. ACL
    • Ant intercondylar fossa of tibia --> med aspect of lat fem condyle
    • Runs obliquely sup and lat
    • Checks forward glide of tibia on femur and limits tibia IR during flex
  8. PCL
    • Post intercondylar fossa of tibia --> lat surface of med fem condyle
    • Runs obliquely medially and ant-sup
    • Checks post displacement of tibia on femur
  9. Meniscofemoral Ligament
    • Runs with PCL
    • Post horn of lat meniscus --> lat aspect of medial condyle
  10. Oblique popliteal ligament
    • Forms floor of popliteal fossa
    • In contact with popliteal ant artery
    • Strengthens post med capsule
  11. Arcuate Popliteal Ligament
    • Y shaped
    • 2 bands (med and lat)
    • Fibular head --> post intercondylar area and lat femoral condyle 
    • Strengthens post lat capsule
  12. Transverse Ligament (Knee Region)
    Connects lat and med meniscus anteriorly
  13. Meniscopatellar Ligament
    • Inferolateral patella --> lat boxers of each meniscus
    • Pulls menisci forward with ext
  14. Alar Fold
    • Lat patella --> med and lat aspects of femoral condyles
    • Keeps patella in contact with femur
  15. Infrapatellar Fold
    • Formed by attachment of patellar fat pad and tendons
    • Acts as a stop gap as its compressed by patella tendon in full flexion
  16. Proximal Tibfib Joint Ligaments
    • Ant Tibfib Ligament = reinforces capsule anteriorly
    • Post Tibfib Ligament = reinforces capsule posteriorly
  17. Medial Meniscus
    • Large, c-shaped, and stable
    • Attached to MCL, fibrous capsule, semimembranosus, and med meniscopatellar ligament
  18. Lateral Meniscus
    • Smaller, circular
    • Attached to popliteus, lat meniscopatellar ligament, and meniscofemoral ligament
  19. Meniscus Function
    • Deepens fossa of tibia
    • Increases congruency of tibia and femur
    • Provides stability to tibiofemoral joint
    • Provides shock absorption and lubrication to knee
    • Reduces friction during movement
    • Improves weight distribution
  20. Movement of Mensici
    • Follow tibia with flex/ext and femoral condyles with IR/ER
    • Med meniscus moves 6 mm, lat 12 mm
    • With isolated tibial rotation, menisci move opposite (tib IR, med meniscus moves ant and lat moves post) 
    • Motions are also influenced by soft tissue
    • Med meniscus pulled post (flex) by semimembranosus and ACL and ant (ext) by med meniscopatellar lig, held firm by MCL and capsule
    • Lat meniscus pulled post (flex) by popliteus and ant (ext) by lat meniscopatellar lig and meniscofemoral lig
  21. Knee Bursae
    • Prepatellar
    • Superficial infrapatellar
    • Deep infrapatellar
    • Suprapatellar
    • Popliteal
    • Semimembranosus
    • Gastrocnemius
    • Pes anserine busra
  22. Prepatellar Bursa
    Between skin and ant distal patella
  23. Superficial Infrapatellar Bursa
    Ant to ligamentum patella
  24. Deep Infrapatellar Bursa
    Between post ligamentum patella and ant tim tuberosity
  25. Suprapatellar Bursa
    Between patella and tibiofemoral joint
  26. Popliteal Bursa
    Post knee, often connected to synovial cavity
  27. Semimembranosus Bursa
    Between muscle and femoral condyle
  28. Gastrocnemius Bursa
    • One for each head
    • Medial bursa usually communicates with semimembranosus bursa
  29. Pes Anserine Bursa
    Between per anserine and MCL
  30. Knee Region Blood Supply
    Descending branch of lat circumflex femoral branch of deep femoral artery
  31. Knee Region Innervation
    • Obturator 
    • Femoral
    • Tibial
    • Common Fibular
  32. Movements of Femoral Condyles During Flex/Ext
    • Initially movement is pure rolling and ends in pure gliding
    • Medial condyle: pure rolling during 1st 10-15 deg of flex
    • During flex, femoral condyles roll post (ACL becomes taught causing condyles to glide ant)
    • During ext, femoral condyles roll ant (PCL becomes taught, condyles glide post) 
    • Walking: normal knee flex ROM = 15 deg (pure rolling of femur on tibia)
  33. Knee: Conjunct Rotations
    • Flex at 10-15 degrees: ACL tightens, femur glides ant (5 degrees further, rolling occurs on lat condyle --> causes conjunct med rotation of tibia)
    • Extension: PCL causes femur to glide posteriorly, condyles roll ant 10-15 deg (further 5 deg of rolling occurs on lat side causing med femoral rotation/ER of tibia)
  34. Screw Home Mechanism
    • 5 degrees of tibia ER (occurs during TKE)
    • Occurs as CKC femoral IR to provide increased stability of joint or OKC tibial ER
    • Unlocking action occurs through action of popliteus
  35. Biomechanics of Prox Tibfib Joint
    • DF of talocrural jt: fib head glides sup and post, shaft ER
    • PF of talocrural jt: fib head glides inf tnad ant, shaft IR