quiz #5 - knee Flashcards
knee joints
tibiofemoral (knee)
patellofemoral
proximal/ superior tibiofibular
mid tibiofibular
distal tibiofibular
tibiofemoral (knee) joint - type & movements
synovial, hinge, diarthrosis, biaxial
gliding, flexion, extension, hyperextension, lateral/external rotation, medial/internal rotation
tibiofemoral (knee) joint - articular surfaces
convex medial & lateral femoral condyles
with concave medial & lateral superior articular surfaces of tibia (tibial plateaus)
tibiofemoral (knee) joint - ligaments
EXTRACAPSULAR: fibrous capsule, patellar (P), medial & lateral patellar retinaculum, tibial/ medial collateral (P), fibular/ lateral collateral (P), oblique popliteal & arcuate popliteal
INTRACAPSULAR: ACL, PCL, posterior meniscofemoral, transverse, coronary (P), medial & lateral menisci
intracapsular/ extracapsular
intra: ACL, PCL
extra: MCL, LCL
anterior cruciate ligament (ACL)
from medial aspect of lateral femoral condyle
to anterior aspect of tibial intercondylar eminence
what does the ACL resist & what is it taut in
resists anterior translation & medial rotation of tibia on femur
taut in hyperextension
posterior cruciate ligament (PCL)
from posterior aspect of intercondylar eminence to lateral aspect of medial femoral condyle
what does the PCL resist & what is it taut in
resists posterior translation of tibia on femur
taut in hyperflexion
medial collateral ligament (MCL) - (tibial collateral Ligament)
resists VALGUS forces
lateral collateral ligament (LCL) - (fibular collateral Ligament)
resists VARUS forces
MENISCUS - function
acts to disperse weight evenly & to reduce friction with movement
medial meniscus
attached to MCL & semimembranosus muscle/tendon
lateral meniscus
attached to PCL & popliteus muscle
how are meniscus attached to each other?
menisci attached to each other ANTERIORLY by TRANSVERSE ligament of knee, & to margins of head of tibia by coronary ligaments
BURSAE
suprapatellar, superficial & deep infrapatellar, prepatellar, popliteal & semimembranosus
4 additional bursae related to: tendon of insertion of biceps femoris, tendons on insertion of sartorius, gracilis & semitendinosus, origins of lateral & medial heads of gastrocnemius
4 main bursa
suprapetella
prepatella
infrapatella
semimembranosus
tibiofemoral (knee) joint - loose packed position
25º flexion
tibiofemoral (knee) joint - close packed position
full extension, lateral rotation of tibia
tibiofemoral (knee) joint - capsular pattern of restriction
flexion first, then extension
NORMAL end feel
flexion: soft tissue or bony approximation
extension: elastic/firm, tissue stretch
ABNORMAL end feel
boggy: joint effusion, ligamentous pathology
springy block: loose body (displaced meniscus)
tibiofemoral (knee) joint - ROM
Flexion: 0-135º
Extension: 0-15º
Internal Rotation: 20-30º
External Rotation: 30-40º
flexion & extension - roll & slide
FLEX: roll = POSTERIOR, slide = POSTERIOR
EXT: roll = ANTERIOR, slide = ANTERIOR
open kinetic chain (kicking a ball)
-flexion: concave tibial plateau rolls & glides
posterior on convex femoral condyles
-extension: concave tibial plateau rolls & glides
anterior on convex femoral condyles
closed kinetic chain (squat)
-flexion: femoral condyles roll & glide posterior on tibial plateau (squatting)
-extension: femoral condyles roll & glide anterior on tibial plateau (moving from squatting to standing)
genu valgum
Q angle greater than 22° in women & 18° in men
= “knocked knees”
genu varum
Q angle less than 0°, distal tibia points medially
= “bow legs”
genu recurvatum
hyperextension of knee
patellofemoral joint - location
small bone in front of knee, embedded in quadriceps (thigh muscle) tendon
called a sesamoid bone
patellofemoral joint - function
acts to increase the biomechanical leverage of quadriceps muscle
patella slides in groove of femur as the knee…
flexes & extends
patella ‘floats’ within substance of quadriceps…
tracking of this bone in femoral groove is dependent on proper mm balance to maintain a central position
patellofemoral joint - type & mvoements
synovial, plane, diarthrosis, triaxial
superior/inferior glide, medial/lateral glide, tilt, rotation
patellofemoral joint - articular surfaces
concave posterior surface of patella
convex trochlear surface of distal anterior femur
patellofemoral joint - ligaments
patellar ligament (tendon)
medial & lateral patellofemoral ligament
patellofemoral joint - loose packed position
full extension
patellofemoral joint - close packed position
full flexion
patellofemoral joint - capsular pattern of restriction
flexion first, then extension
proximal/ superior tibiofibular joint - type & movements
synovial, plane, diarthrosis, uniaxial
gliding
proximal/ superior tibiofibular joint - articular surfaces
articular facet on fibular head
facet on lateral tibial condyle
proximal/ superior tibiofibular joint - ligaments
fibrous capsule, anterior & posterior superior tibiofibular, lateral collateral, upper interosseous membrane
mid-tibiofibular joint - type & movements
fibrous, (interosseous) syndesmosis, amphiarthrotic, uniaxial
slight
mid-tibiofibular joint - articular surfaces
interosseous membrane connecting shafts of tibia & fibula
mid-tibiofibular joint - ligaments
interosseous membrane
distal/ inferior tibiofibular joint - type & movements
fibrous, syndesmosis, amphiarthrosis, uniaxial
gliding
distal/ inferior tibiofibular joint - articular surfaces
articular area on inferior end of fibula
facet on inferior end of tibia
distal/ inferior tibiofibular joint - ligaments
interosseous membrane (lower), anterior & posterior inferior tibiofibular ligaments
distal/ inferior tibiofibular joint - movement: 1-2mm during dorsiflexion at ankle joint
dorsiflexion causes fibula to move superiorly, which also causes proximal/superior tibiofibular joint to be stressed
screw home mechanism
= key element to knee stability for standing upright
-during knee extension, tibia glides anteriorly on femur & PCL elongates
-during last 20º of knee extension, anterior tibial glide persists on tibia medial condyle (articular surface longer) prolonged anterior glide on medial side produces EXTERNAL tibial rotation (“screw-home” mechanism)
*reverses during knee flexion
gait cycle
tibia internally rotates during swing phase (knee flexion)
tibia externally rotates during stance phase (knee extension)