KINES: Knee Complex Flashcards
what forms the knee complex
tibiofemoral and patellofemoral joint
what type of joint is the tibiofemoral joint
double condyloid or modified hinge joint
what are the 2 planes of movement of the knee joint
primary - sagittal for flex/ext
secondary - transverse for tibial ER and IR
what type of joint is the patellofemoral joint
non-synovial or false
between the 2 femoral condyles which is larger
larger medial condyle
compare the position of medial and lateral condyle
medial - shifted posteriorly and more distal
lateral - shifted anteriorly and more inline w shaft of femur
what results due to the larger medial condyle
greater radius of curvature and some rotatory movement due to the imbalance of the shape
which of the tibial plateaus are larger
media to match the condyles
discuss the tibiofemoral alignment
shaft of femur is not in line w tibia - obliquely oriented
normal physiologic valgus angle
175-185 degrees
anatomical/longtudinal axis of femur
oblique
anatomical/longtudinal axis of tibia
vertically oriented
what happens if physiologic angle is greater than 185
genu valgum/knock knees
what happens if physiologic angle is less than 185
genu varum/bow legs
what structure is stretched in genu valgum
medial collateral ligament
what structure is stretched in genu varum
lateral collateral ligament
what is mechanical axis
weight bearing line - passes at center of hip joint, knee joint and ankle joint
what happens to mechanical axis during single leg stance
axis shifts medially - compressive force on medial and distractive on lateral
normal value of Q angle
10-15 degrees
males - 14 degrees
female - 17 degrees
why do females have higher q angles
bcs of wider pelvis and short stature
what does the q angle represent
the vector for combines pull of the quads and patella tendon; influences amount of force generated
where is q angle measured
ASIS-midpoint of patella
tibial tubercle to midpoint of patella
what are menisci
fibrocartilaginous discs - gel like structure
purpose of menisci
increases concavity of tibial plateau and increases congruence
3 functions of menisci
shock absorber and pressure distribution
friction reduction
absence results to injuries
compare the medial and lateral menisci
lateral - smaller and circle
medial - larger and C-shaped
describe the structure of menisci
thick on outer/periphery and thinner on central area
compare the periphery and central area of menisci
cappilaries only present on periphery
inner aspect is avascular
explain the healing process in menisci
injuries on outer periphery will have better prognosis than inner aspect
what connects the 2 anterior horns of menisci
transverse ligament
what are the attachments of the menisci
transverse ligament
collateral ligaments
joint capsule
tendons
coronary ligaments
function of coronary ligaments
stabilizes meniscus betw femur and tibia
keeps menisci kept in place in all motions - absence = unstable
attachments of medial meniscus
MCL
ACL - anterior horn
PCL - posterior horn
semimembranosus
attachments of lateral meniscus
LCL
ACL - common tibial attachment
popliteus
what influences meniscal motion
structures around it dictate amount of stabilization
compare medial and lateral meniscus in terms of stabilization
medial has more attachments kaya greater risk for injury kase not as freely movable
CPP of knee
full knee extension with tibial ER
OPP of knee
25-30 deg flexion
what are the layers of joint capsule
fibrous capsule and synovial membrane
which is the superficial layer of the joint capsule
fibrous capsule
which is the deep layer of the joint capsule
synovial membrane
attachments of the fibrous capsule
distal femur, proximal tibia, patella, quadriceps and patellar tendon
function of fibrous capsule
creates a tight seal and encloses synovial fluid
what forms the extensor retinaculum
fibrous capsule
lateral patellar retinaculae
medial patellar retinaculae
function of synovial membrane
secrete and absorb synovial fluid
what is the position of synovial fluid in knee extension
pushed anteriorly
what is the position of synovial fluid in knee flexion
pushed posteriorly
what is the position of synovial fluid in knee OPP
even distribution of fluid
what happens to synovial fluid in injury
inflammation or swelling - compression of structures nd pain
patient assumes semiflexed bcs comfort
function of fat pads
shock absorbers
reduce frictional surgace
what are the fat pads
anterior suprapatellar
posterior suprapatellar
infrapatellar
other name for infrapatellar fat pad
hoffa’s fat pad
describe innervation in fat pad
very rich kaya very sensitive cla
too muhc compression = pain = fat pad impingement syndrome
describe the synovial membrane in embryonic stage
separated into lateral and medial compartments
divided by synovial septum