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54 Cards in this Set

  • Front
  • Back
What are the two components of layer I?
Sartorius associated fascia
Medial paterllar retinaculum
What two structures lie between layers I and II?
Gracilis
Semitendinosus
What are the four components of layer II?
Superficial medial collateral ligament (MCL)
Posterior oblique ligament (POL)
Medial patellofemoral ligament (MPFL)
Semimembranosus
What are the two components of layer III?
Deep MCL
Capsule
What are three components of layer I?
Iliotibial (IT) band
Biceps
Fascia
What are the two components of layer II?
Patellar retinaculum
Patellofemoral ligament
What are the four components of layer III?
Arcuate ligament
Fabellofibular ligament
Capsule
Lateral collateral ligament (LCL)
What three structures make up the posteromedial corner?
Semimembranosus insertions
POL (adductor tubercle origin)
OPL (oblique popliteal ligament)
What is the function of the posteromedial corner?
Rotatory stability
What five structures make up the posterolateral corner?
Popliteus
Popliteofibular ligament
Lateral capsule
Arcuate ligament
Fabellofibular ligament
What exam finding is suggestive of disrupted PLC? What is the posterior cruciate ligament (PCL) is also disrupted?
Asymmetric external rotation (ER) at 30 degrees knee flexion: isolated PLC injury
Asymmetric ER at 30 and 90 degrees PLC and PCL injuries
What is the orientation of the superficial fibers?
Radial
What is the orientation of the deep fibers?
Predominantly circumferential
Interspersed radial "tie fibers"
What type of cartilage makes up the meniscus?
Fibroelastic cartilage
What is the predominant collagen type present within the meniscus?
Predominantly type of I collagen
What cell type makes up the meniscus?
Fibrochondrocytes
How is the meniscus innervated? Where is the meniscus especially well innervated?
Peripheral two thirds innervated with type I & II nerve endings
Especially well innervated in the posterior horn (mechanoreceptions)
What vessels provide the meniscal blood supply?
Geniculates supply blood to peripheral one third
What percentage of force does the meniscus transmit in extension? What percentage is transmitted in flexion?
50% in extension
90% in flexion
Is the medial or lateral meniscus more mobile? Why? Why is this clinically important?
Lateral meniscus is more mobile
Because popliteus interrupts lateral meniscal attachment
May contribute to more common medial tears
What is the classic magnetic resonance imaging (MRI) appearance of a displaced bucket-handle tear of the posterior horn of the medial meniscus?
Posterior horn of lateral meniscus to medial femoral condyle with PCL
Which of the meniscofemoral ligaments is anterior? Which is posterior?
Humphrey's (anterior)
Wrisberg (posterior)
What are the two main collagen types within the ACL and what is the relative proportions of each?
90% type I
0% type II
What vessels supplies the ACL? What supplies the fat pad?
Middle geniculate supplies ACL
Inferior geniculates supplies fat pad
What is the strength of the native ACL?
2100N
What are the two bundles of the ACL?
Anteromedial
Posterolateral
AT what flexion angle is the anteromedial bundle at maximum tension?
60 degrees
At what flexion angle is the posterolateral bundle at maximum tension?
15 degrees
What are the two bundles of the PCL?
Anterolateral
Posteromedial
At what flexion angle should the anterolateral bundle be tensioned intraoperatively?
90 degrees
At what flexion angle should the posteromedial bundle b tensioned?
30 degrees
How can the MCL or LCL be tested in isolation? What happens in extension?
Valgus or varus stress at 30 degrees flexion isolated the respective collateral ligament
In extension, the PCL also contributes to stability
What os the better restraint against valgus stress: superficial or deep MCL?
Superficial
What two structures does the superior geniculate (lateral, medial branches) supply?
Patella
PCL
What three structures does the middle geniculate supply?
ACL
PCL
Collaterals
What two structures does the inferior geniculate (lateral, medial branches) supply?
Menisci
Fat pad
In what interval does the lateral branch of the superior geniculate lie? With what procedure is this branch most commonly at risk?
Femur/vastus lateralis
At risk with lateral release
The inferior geniculate branch lies posterior to what anatomic landmark?
Posterior to LCL
Where does the tibial nutrient artery enter?
Below PCL insertion
What three facets make up the articular surface of the patella?
Lateral facet
Medial facet
Odd facet
What is the Wiberg classification?
Type I: medial & lateral facets are equal
Type II & III: medial facet smaller than lateral
Type IV: (Jagerhut patella): no medial facet present
What are the two most likely sites of bony injury following lateral paterllar dislocation?
Medial facet of patella
Superior lateral condyle of femur
Over what structure is the medial knee approach centered?
Adductor tubercle
Over what structure is the lateral knee approach centered? What is the interval for dissection?
Centered over Gerdy's tubercle
Interval: iliotibial (IT) band/biceps femoris
How far distal does the knee capsule extend? Where is the most distal extent?
15 mm distal extent
Most distal extent is posterior to fibula
Within what tendon odes the fabella lie?
Lateral gastrocnemius
The personal nerve lies at the posterior border of what structure?
Biceps gastrocnemius
What is the screw home mechanism?
Femur internal rotation during the last 15 degrees of knee extension
Where does the lower extremity mechanical axis pass through the knee?
Medial to the medial tibial spine
Starting at vertical, what is the relationship of the mechanical and anatomic axes?
Mechanical axis lies in 3 degrees of valgus
Anatomic axis is 9 degrees of valgus
So, anatomic axis is 6 degrees of valgus relative to mechanical axis
How is the Q angle measured?
Anterior superior iliac spine (ASIS) to patella to tibial tubercle
What is the approximate normal value of the Q angle in extension? In flexion?
15 degrees in extension
8 degrees in flexion
The highest joint reaction forces in the knee are experienced where? At what phase of gait?
Medially
Stance phase
Where id the highest joint reaction force experienced in the patella?
Laterally