Knee Flashcards
What is the main function of the knee?
Stability, allow for mobility in clearing during gait
Function of the fibula
lateral stabilizer– indirect attachment for LCL, but not true contributor to knee joint
Which is larger, lateral or medial plateau?
Medial
Patella’s base is _______ and apex is _______-
base superior
apex inferior
Anterior surface is ________, posterior is ______________
ant = convex in all directions post = both convex and concave. covered with cartilage.
PRIMARY function of patellla
increase angle of application (MA of quadriceps)
SECONDARY function of patella
protect quad tendon from excessive friction
Genu Valgum excessive angle
Greater than 170
Genu Varum excessive angle
Greater than 180
Genu valgum compresses the knee ______
Genu varum compresses the knee _______
valgum = laterally
varum = medially
Most relaxed position of the TF capsule
Slight flexion (15 to 30 degrees)
Blood supply of menisci is greatest where?
Periphery
red-red zone –> red-white zone–>white-white zone
Medial meniscus shape vs lateral meniscus shape
medial = semicircular lateral = circular
Primary functions of menisci
reduce compressive forces, stabilize joint during motion
In what knee position can internal or external knee rotation occur?
Slightly flexed
Flexion/Extension AOR
Medial-Lateral
Closed Chain Arthrokinematics of Knee EXTENSION
Prox on distal = femur on tibia = convex on concave = femoral condyles roll anteriorly and glide posteriorly
Open chain arthokinematic of knee EXTENSION
Distal on proximal = tibia on femur = concave on convex = tibia rolls and glides anteriorly
Arthrokinematics of screw home mechanism- open chain
tibia on femur = popliteus initiates tibial IR
Arthrokinematics of screw home mech - closed chain
Femur on tibia = popliteus initiates femoral ER
Open chain AK of knee flexion
tibia rolls and glides posteriorly
Closed chain AK of knee flexion
femoral condyles roll posteriorly and glide anteriorly
Is MCL vascularized?
Yes
MCL protects more when it is _______
Extended
MCL and LCL resist more when they are in slight
flexion (since they’re not as taught)
Primary function of ACL
anterior displacement of the tibia on femoral condyles
Fibers of ACL taught with knee how?
Close to full extension
How is ACL most commonly torn?
Knee slightly flexed and tibia is rotated to either direction
(forceful quad contraction pulls tibia anteriorly whichs trains ACL)
PCL is taught in knee
flexion
Knee Flexed 135– where is pt of max contact between patella and femur?
Superior pole of patella
Knee Flexed 90 – where is pt of max contact between patella and femur?
Middle of patella
Knee Flexed 20– where is point of max contact between patella and femur?
Inferior pole of patella
As knee extends…max contact between patella and femur…
moves from superior pole to inferior pole of patella
Where is Q angle measured?
ASIS to mid-patella, tibial tuberosity to mid-patella
Normal Q angle for women and men
15 women, 11 men (>15 is abnormal)… used to assess pull on patella
In sitting– external torque of flexed knee then extended knee
flexed knee: 0
extended knee: near 100
In standing (femur on tib) –external torque of flexed knee then extended knee
100 to 0 (in extension you hang on your ligaments)
Maximal torque of hamstrings
about 30 degrees (near full knee extension)
Pes anserine function in knee
Provide medial stability, internally rotates tibia
Popliteus function in knee
IR, flexor – unlocks the knee
