Flashcard Set Preview
Side ASide B
What are the major features of Medial Collateral Ligament?
1) Wide, band-like ligament 2) 2 major portions: Deep & Superficial 3) Continuous with the capsule
What does the MCL resist?
VALGUS (and some fibers resist medial and lateral rotation)
What is the function of the MCL?
To stabilize the knee against valgus stress and resist rotational and anterior forces on tibia.
What are the major features of the Lateral Collatoral Ligament?
1) Rounded, pencil-like ligament. 2) Easy to palpate 3) NOT continuous w/ capsule
What does the LCL resist?
VERUS (and extreme rotations at knee)
What are the attachments of Anterior Cruciate Ligament (ACL)?
Prox.: Medial aspect of lateral femoral condyle Distal: Anterior aspect of intercondylar eminence of tibia.
What are the functions of the ACL?
1) STABILIZE knee from displace tibia Anteriorly on femor "anterior drawer" 2) Draws tight on excessive Valgus, Extension and restrains IR.
What are the attachments of Posterior Cruciate Ligament (PCL)?
Prox: Lateral aspect of medial femoral condyle at intercondylar notch. Distal: Posterior aspect of intercondylar eminence of tibia.
What are the functions of the PCL?
Prevent displacement of tibia posteriorly "posterior drawer"
What do the PCL and ACL do together?
Hold knee together and allow normal movements
What makes up the terrible triad?
1) Medial collateral ligament 2) medial meniscus 3) anterior cruciate ligament
What is closed packed position for leg at knee?
Full extension with ER
Patella surface--Posterior what texture? Anterior: what texture?
Posterior: smoothe Anterior: rough for attachment of fibers and entrance of blood vessels
Surface of femur--Define CAM-shaped
Radius greater in some places than in others. Effects axis of motion
Knee is more stable in which position: flexion or extension?
Restoring flexion of knee at last 10 degrees: easy or hard? Why?
It is hard because you have to move joint surfaces further.
Patella is developed where?
Functions of the Patella
1) redirect the line of pull of the quads 2) prevents excessive wear on the tendon 3) Increases efficiency of the quads in extending leg
Patella: Medial base
Point of attachment of Vastus Medialis
Patella: Lateral base
Point of attach: Vastus Lateralis
Ligaments that reinforce capsule: Anterior
Medial and Lateral Retinaculae
Ligaments that reinforce capsule: Laterally
Ligaments that reinforce capsule: Medially
Medial Collateral ligament
1) Inside Joint cavity but by passes intercondylar space. 2) Excludes the cruciate ligaments from being intrasynovial
Which gets more injured: Posterior cruciate or Anterior cruciate ligaments?
Pronation of foot--combo of what move?
Mostly Eversion, some lateral rotation and dorsiflexion.
Supination of foot--combo of what move?
Mostly Inversion, some medial rotation and plantar flex.
Medial meniscus has what shape and where does it attach?
"C" shaped and it attaches anteriorly and posteriorly on the intercondylar eminence.
Medial meniscus: How is stability reinforced?
The deep portion of the medial collateral ligament
Which is more susceptible to injury: Medial or Lateral Meniscus? Why?
Medial meniscus b/c it is much less mobile and medial condyle more mobile than lateral condyle. More likely to be caught & torn
Lateral meniscus has what shape and where does it attach?
"O" shape. Major attachment posteriorly from popliteus tendon.
What is Condromalacia of patella?
The cartalege softening and fibrillation.
Motion of knee: What are the 2 main mechanisms?
Sliding and Rocking
Knee as "Hinge" joint. Does it occur around single axis?
No. The axis is constantly changing throughout range of flexion.
"Screw Home Mechanism" describes what?
The fact that at terminal knee extension, the tibia EXTERNALLY rotates on femur approx. 15 degrees. That makes it screw home or "lock" knee
What is the effect of the Screw Home Mechanism?
To allow a person to stand fully extended for long time w/o use of muscle power or knee collapsing into knee flexion
Reason 1 why Screw Home Mechanism occurs
As knee moves to full EXTENSION the ANTERIOR movement of tibia is stopped by the ACL.
Reason 2 why Screw Home Mechanism occurs
B/c ACL is attached to LATERAL femoral condyle, motion is stopped.
Reason 3 why Screw Home Mechanism occurs
B/c medial femoral condyle is longer than lateral condyle and not fixed by ACL, it will continue to move POSTERIORLY on tibia--causes EXT Rot.
What two lines form the Q angle?
1) line from ASIS to center of patella 2) line following line (direction of fibers) of patellar tendon
Why is Q angle significant?
1) Abnormal biomechanics of patella are attributed to excessive Q angles. 2) Can result in retro patellar pain
To work with Q angle, what do you need to strengthen?
ER at hip and VMO
True or false: The lateral meniscus has an attachment to lateral collateral ligament
Both menisci are attached to what?
Synovial and fibrous layers of the joint capsule
True or false: The medial meniscus is anchored firmly to the tibial collatoral ligaments?
Mensici are most likely to be torn when knee is flexed or extended?
What is one of 3 main functions of Menisci?
1) Joint nutrition (synovial fluid & lub)
What is second of 3 main functions of Menisci?
2) Increase surface area for weight distribution
What is third of 3 main functions of Menisci?
3) Increase stability of knee
Common severe athletic injury to knee would result in tearing of which 2 ligaments and 1 meniscus?
Medial collateral and anterior cruciate ligaments. And often: medial meniscus
Rupture of which ligament can result from automibile accident where person crashes into "dashboard"?