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The knee consists of which compartments?
Lateral and medial compartments of the tibiofemoral and patellofemoral joints TERM 2
Motion at the knee occurs in how many
planes?
DEFINITION 2 2flexion/extensioninternal/external rotation TERM 3
How is the strong functional association
within the lower limb joints reflected?
DEFINITION 3 that about 2/3 of the muscles that cross the knee joints all cross either the hip or ankle TERM 4
During the swing phase of walking, the knee
does what?
DEFINITION 4 flexes to shorten the functional length of the lower limbotherrwise foot wouldn't clear the ground TERM 5
During the stance phase of walking, the knee
does what?
DEFINITION 5 remains slightly flexed allowing shock absorption, conservation of energy and transmission of forces through the lower limb
Stability of the knee is primarily based on
what?
soft-tissue constraints rather than bony configuration TERM 7
What is the purpose of epicondyles?
DEFINITION 7 to provide elevated attachment sites for the collateral ligaments TERM 8
Fxn of the intercondylar
notch
DEFINITION 8 separates the lateral and medial condyles forming a passageway for the cruciate ligaments TERM 9
Fxn of the intercondylar
groove
DEFINITION 9 articulates with the posterior side of the patella forming the patellofemoral joint TERM 10
The sloping sides of the intercondylar groove
form what?
DEFINITION 10 lateral and medial facets
How is the fibula attached to the tibia?
proximal and distal tibiofibular joints TERM 17
Primary fxn of the tibia?
DEFINITION 17 to transfer weight across the knee and to the ankle TERM 18
Fnx of medial and lateral condyles of the tibia
DEFINITION 18 forms articular surfaces with the distal femurtop surface referred to as tibial plateau which forms the medial and lateral compartments of the tibiofemoral joint TERM 19
Difference between the medial and lateral
surfaces of the tibial plateau
DEFINITION 19 larger medial surface is slightly concavelateral surface is flat to convex TERM 20
Fxn of the intercondylar
eminence
DEFINITION 20 separates the articular surfaces down the midline forming medial and lateral tubercles
Fxn of the intercondylar
areas
flank both ends of the eminence where the cruciate ligaments and the menisci attach along the intercondylar region of the tibia TERM 22
Fxn of the tibial tuberosity
DEFINITION 22 serves as distal attachment for the quads femoris, via patellar tendon TERM 23
The patella is what kind of bone?
DEFINITION 23 largest sesamoid bone in the body TERM 24
Anatomical features of the
patella
DEFINITION 24 curved base superiorly and pointed apex inferiorly for attachment of the patellar tendon between the apex and tibial tuberosity TERM 25
Posterior articular surface of the patella
DEFINITION 25 covered with articular cartilage 4-5 mm thick to help disperse large compression forces across the jointpart of surface articulates with intercondylar groove of femur forming patellofemoral joint
The capsule of the knee receives significant
reinforcement from what?
muscles, ligaments, fascia TERM 32
How many reinforced regions of the capsule
of the knee are there?
DEFINITION 32 5 regions:1. Anterior2. Lateral3. Posterior4. Posterior- lateral5. Medial TERM 33
Anterior capsule of the knee
DEFINITION 33 attaches to patella and patellar tendon with reinforcement by quads and medial+lateral patellar retinacular fibers TERM 34
Functions of the patellar retinacular fibers
DEFINITION 34 extensions of the CT covering vastus lateralis, vastus medialis and IT bandconnects to femur, tibia, patella, quadricep and patellar tendons, collateral ligaments and menisci TERM 35
Lateral capsule of the knee
DEFINITION 35 reinforced by the lateral collateral ligament, lateral patellar retinacular fibers and the IT bandmuscle stability from biceps femoris, tendon of popliteus and lateral head of gastroc
Posterior capsule of the knee
reinforced by the oblique popliteal ligament and arcuate popliteal ligamentmuscle reinforcement by popliteus, gastroc and hamstrings, especially tendon of semimembranosus TERM 37
What limits hyper-extension in the
knee?
DEFINITION 37 no bony block so only muscles and posterior capsule can limit hyper-extension TERM 38
Posterior-lateral capsule of the knee
DEFINITION 38 reinforced by the arcuate popliteal ligament, lateral collateral ligament and popliteus muscle and tendontogether these structures are know as the "Arcuate Complex" TERM 39
Medial capsule of the knee
DEFINITION 39 reinforced by medial patellar retinacular fibers (aka medial patellofemoral ligament, medial collateral ligamentposterior 1/3 of medial capsule thickened and called posterior-medial capsule or posterior oblique ligamentmuscle reinforcement by expansions of semimembranosus tendon and pes anserinus (sartorius, gracilis, semitendinosus) TERM 40
The internal surface of the capsule of the
knee is lined with what?
DEFINITION 40 a synovial membrane
How are the menisci anchored to the tibia?
anterior and posterior horns and cornonary ligaments TERM 47
Coronary ligaments
DEFINITION 47 loose allowing for movement of the menisci especially the lateral meniscus TERM 48
What connects the two menisci anteriorly?
DEFINITION 48 transverse ligament TERM 49
Muscle attachments to the menisci
DEFINITION 49 quadriceps andsemimembranosus to both meniscipopliteus laterally TERM 50
Blood supply to the menisci
DEFINITION 50 greatest near external border with supply provided by capillaries in the synovial membrane and capsuleinternal border is avascular
Primary fxn of menisci
reduce compressive stress across the tibiofemoral joint at any one point by increasing joint contact areastabilize joint during motion, lubricates articular cartilage, provides proprioception and helps to guide knee arthrokinematics TERM 52
How are menisci most often injured?
DEFINITION 52 forceful axial rotation of the femoral condyles over a partially flexed and wt bearing knee that can pinch and dislodge meniscus TERM 53
Which meniscus is more frequently injured
and why?
DEFINITION 53 medial 2x more because it is more stable and has less movementtypically involves a valgus force along with axial rotation TERM 54
The risk of developing chronic or traumatic
meniscus tears is dependent on what?
DEFINITION 54 poor alignmentinstabilityhistory of ligamentous tear (ACL) which increased anterior femoral movement TERM 55
Innervation of the meniscus
DEFINITION 55 free nerve ending (nociceptors)mechanoreceptors (ruffini corpuscles, pacinian corpuscles and golgi tendon organs) -- proprioception
External vs Internal rotation of the knee
external rotation range exceeds internal rotation by 2: TERM 62
When is axial rotation restricted?
DEFINITION 62 when knee is extendedpassive tension in the stretched ligaments, capsule and increased bone congruency block rotation TERM 63
Axial rotation of the knee occurs in which two
ways?
DEFINITION 63 tibial-on-femoralfemoral-on-tibial TERM 64
The naming of axial rotation of the knee is
based on what?
DEFINITION 64 based on the position of the tibial tuberosity relative to the anterior distal femur TERM 65
Tibial on femoral external rotation of the knee
DEFINITION 65 occurs as the tibia rotates externally relative to a stationary femurfits definition of external rotation of the knee since motion ends up with tibial tuberosity located lateral to anterior distal femur
Femoral on tibial external rotation
occurs as the femur rotates internally relative to a stationary tibia and footfits definition of external rotation of the knee since motion ends up with tibial tuberosity located lateral to anterior distal femur TERM 67
Tibial on femoral extension
DEFINITION 67 articular surface of the tibia rolls and slides anteriorly on the femoral condylesmenisci pulled anteriorly by contracting quads TERM 68
Femoral on tibial extension
DEFINITION 68 femoral condyles roll anteriorly and slide posteriorly on surface of tibiaquads direct roll of femoral condyle and stabilizes menisci TERM 69
Locking the knee in full extension requires
what?
DEFINITION 69 10 degrees of external rotation"screw-home" rotation based on twisting of knee during last 30 degrees of extension TERM 70
Screw home external rotation is described as
what?
DEFINITION 70 conjunct rotation due to its linking to flexion and extension kinematicsit cannot be performed independently
Function of LCL
provides resistance against varus (Adducting) force and knee extension TERM 77
Secondary function of the collateral ligaments
of the knee
DEFINITION 77 to produce a generalized stabilizing tension at the knee throughout sagittal plane ROM TERM 78
Cruciate ligaments of the knee in general
DEFINITION 78 intracapsular and convered with synovial liningBlood supply is via small vessels located in the synovial membrane Named according to their attachment on the tibia TERM 79
General functions of ACL and PCL
DEFINITION 79 Working together, the cruciate ligaments resist extremes of motionResist anterior-posterior shear forces created between tibia and femurProvide multi-plane stability, primarily sagittal plane movementsGuide natural arthrokinematicsProvide proprioception TERM 80
Connection of the ACL on tibia
DEFINITION 80 Runs from anterior tibia to the medial side of the lateral femoral condyleRuns superior, lateral and posterior
2 bundles of ACL
named according to their tibial attachmentsAnteriomedial bundle (AMB)Posteriolateral bundle (PLB) TERM 82
When is the ACL taut?
DEFINITION 82 Some fibers are taut throughout entire sagittal plane ROMMost fibers bundle become increasingly taut as the knee approaches full extension TERM 83
What happens in the knee during the last 50-
60 degrees of end range extension
DEFINITION 83 the quadriceps pulls the tibia anteriorlytension in the ACL limits that tibial anterior translation TERM 84
Anterior drawer test
DEFINITION 84 involved pulling the proximal end of the tibia forward with the knee flexed to 90 degreesin normal knee ACL provides 85% of total passive resistance to anterior translation of tibia TERM 85
Mechanisms of ACL injury
DEFINITION 85 most through non-contact landing from jump quickly and forcefully decelerating cutting or pivoting over single planted lower limb excessive hyperextension with foot planted
Describe the connection between the PCL and
tibiofemoral joint in flexion
With prone knee flexion, the hamstrings slide the tibia posteriorThe posterior slide is limited by passive tension in the PCLHamstrings are called PCL antagonists TERM 92
Posterior drawer test
DEFINITION 92 involves pushing the proximal end of the tibia posteriorly with the knee flexed to about 90 degreesPCL provides 95% of total passive resistance to posterior translation of tibia TERM 93
Secondary fxn of PCL
DEFINITION 93 limit the extent of anterior translation of the femur relative to the lower fixed legactivities like rapid descent into a deep squat, PCL prevents femur from slipping off anterior edge of tibia TERM 94
Common mechanisms of PCL injury
DEFINITION 94 Falling over a fully flexed kneeProximal tibia is the first point of contact with the ground)Dashboard injury- MVA TERM 95
What is the patellofemoral joint?
DEFINITION 95 interface between theArticular surface of the patella and intercondylar groove of femur
Local stabilizers of the patellofemoral joint
Quadriceps forceFit of the joint surfacesPassive restraint from the surrounding retinacular fibers and capsule TERM 97
Tibial-on-femoral patellofemoral joint
movements
DEFINITION 97 Patella slides relative to fixed intercondylar groove of femurPatella follows the direction of the tibia during knee flexion (due to the bony attachment of the patellar tendon to tibial tuberosity) TERM 98
Femoral-on-tibial joint movements
DEFINITION 98 Intercondylar groove of femur slides relative to fixed patellawith the patella held in place by the patellar tendon TERM 99
Patellar contact on the femur at 135 degrees
flexion
DEFINITION 99 patella contacts the femur near its superior polePatella rests below the intercondylar grooveLateral facet and odd facet articulate with the femur TERM 100
Patellar contact on the femur at 90 degrees
flexion
DEFINITION 100 Contact point is migrating toward inferior pole--but is not there yet
