knee Flashcards
(70 cards)
tibiofemoral joint - joint type
synovial double condyloid/modified hinge
t/n: this is because of voluntary control of movement is possible in 2 planes (saggital/transverse)
tibiofemoral joint (2) planes
(2) DOF:
1) sagittal - flex/ext.
2) transverse plane - tibial ER/IR
patellofemoral joint - joint type
non-synovial joint/false joint
tibiofemoral joint anatomy (femoral condyles)
FEMORAL CONDYLES
larger medial FEM condyle
- greater radius of curvature
- shifted a bit POSTERIROLY/projects more DISTALLY
lateral FEM condyle
- shifted ANTERIORLY (more directly in line with the shaft of femur)
t/n: there is some ROTATORY movement happening because of IMBALANCE when it comes to lat/med condyles SHAPE
tibiofemoral joint anatomy (tibial condyles & tibial plateaus)
TIBIAL CONDYLES
larger medial TIB condyle / smaller lateral TIB condyle (same w/ femoral)
TIBIAL PLATEAUS
larger medial TIB plateau / smaller lateral TIB plateau (in order to match two tibial condyles)
(3) tibiofemoral alignments
1) physiological valgus angle/anatomical longitudinal axis of femur
2) mechanical axis/weight-bearing line
3) q angle/quadriceps angle
physiologic valgus angle
- anatomical/longitudinal axis of femur
- normal values: 175-185 (180 ave)
- crosses MIDLINE
genu valgum
- knock knees
- greater than 185 deg
- MEDIAL COLL. ligament STRETCHED
- LATERAL COLL. ligament COMPRESSED
genu varum
- bow legs
- lesser than 185 deg
- MEDIAL COLL. ligament COMPRESSED
- LATERAL COLL. ligament STRETCHED
mechanical axis/weight-bearing line
- transmits weight DOWN TO LE / passes through MECHANICAL AXIS
- passes CENTER OF
1) hip joint
2) knee joint
3) ankle joint
mechanical axis during single-leg stance
- shifts MEDIALLY
- MEDIAL aspect COMPRESSIVE FORCE / LATERAL aspect MORE DESTRUCTIVE/TENSILE FORCE
Q angle
- quadriceps angle
- normal value: 10-15 deg
- male ave: 14 deg / female ave: 17 deg (wider pelvis/short stature)
- INTERSECTION lines FROM:
1) ASIS to midpoint of patella
2) tibial tubercle to midpoint of patella - represents vector for combined pull of quads fem & patellar tendon
- will influence the amt. of force that quadriceps muscle & patellar tendon are generating
menisci of the knee characteristics
- fibrocartilaginous discs (gel-like structure)
- reduces frictional forces
- increases concavity of tibial plateau > increases congruence of joint
- wb function:
1) shock absorber
2) pressure distribution
medial vs lateral menisci (anatomical config.)
MEDIAL
- larger
- C shape
- thick on the outside (on periphery)/thinner on central area
LATERAL
- smaller (almost 4/5 of a circle)
- thick on outside (on periphery)/thinner on central area
(4) menisci attachments
1) transverse ligament
- connecting 2 anterior horns of lateral and medial meniscus
2) coronary ligaments
- stabilize meniscus between femur and tibia (imagine putting a coin in that space > absence of coronary lig. > meniscus unstable) / in place no matter what movement
3) joint capsules
4) tendons of some muscles
medial menisci vs lateral menisci (attachments)
MEDIAL
- MCL
- ACL (anterior horn)
- PCL (posterior horn)
- semimembranosus
LATERAL
- LCL
- ACL (common tibial attachment)
- popliteus
t/n: meniscal motion is influenced by these structures > will dictate stabilization of menisci
medial menisci vs lateral menisci (stability/mobility)
medial meniscus = more attachments = more stable
- medial meniscus being stable cannot go/move with knee joint = has greater risk for injuries
lateral meniscus = less attachments = more mobile
- since LE has many functional activities/involves lots of movements, it requires movement of menisci (lateral)
knee joint OPP/CPP
OPP
- slight knee flexion (25-30 deg)
- not stretched too much
CPP (bony/lig)
- full knee ext.
- tibial ER
knee joint capsule characteristics
- very thick
- has 2 layers
knee joint capsule (2) layers
1) fibrous capsule/layer
2) synovial membrane/sheath
knee joint capsule: fibrous capsule/layer (characteristics & function)
- superficial
- attached to distal femur/proximal tibia
- attaches to patella/quadriceps tendon/patellar tendon
- creates TIGHT seal
- is part of EXTENSOR RETINACULUM
- ENCLOSES synovial fluid
knee extensor retinaculum (3) contents
1) lateral patellar retinaculum
2) medial patellar retinaculum
3) fibrous capsule
knee joint capsule: synovial membrane/sheath (characteristics & function)
- deeper
- thinner
- SECRETE and ABSORB synovial fluid
knee joint: synovial fluid
- moves when we move tibiofemoral joint (extension = anteriorly / flexion = posteriorly)
- semi-flexed position (usual position of comfort) = equal distribution of fluid / does not impinge any pain-sensitive structures being controlled on CENTRAL area
t/n: if knee joint is injured > inflammation > swelling > excessive fluid in synovial cavity > compression of structures in joint