menisci

Question 1

menisci are

Answer 1

biconcave fibrocartilaginous tissue b/w the articulating surfaces of the tibia and the femur

Question 2

medial meniscus shape

Answer 2

semi-lunar ( C-shaped)

wider posteriorly than anteriorly

Question 3

lateral meniscus

Answer 3

approx 4/5 of a circle

Question 4

“horns”

Answer 4

open ends of the menisci

attached to the tibial intercondylar tubercles

Question 5

how’re the medial and lateral menisci attached to the tibia

Answer 5

to their periphery by coronary ligaments

Question 6

how’re the menisci attached to the patella

Answer 6

patellomeniscal or patellotibial ligaments

Question 7

what attaches the anterior horns

Answer 7

transverse ligament

Question 8

medial meniscus has attachments to

Answer 8

MCL and semitendinosus

Question 9

lateral meniscus has attachments to

Answer 9

PCL

popliteus

medial femoral condyle

Question 10

which menisci is more firmly attached

Answer 10

medial meniscus

can’t deform or move as much –> injured more often

Question 11

wedged shaped

Answer 11

thicker at the periphery

thinner centrally

Question 12

functions of the mensici

Answer 12

stability

lubrication and nutrition

shock absorption

mobility

vascularity

Question 13

stability

Answer 13

the menisci deepen the fit b/w the relatively flat surfaces of the tibial plateaus and the convex surfaces of the femoral condyles

Question 14

where is stability greatly important

Answer 14

lateral compartment

convex on convex (femoral condyles on tib)
–> meniscus improves stability

Question 15

in a WB knee joint

Answer 15

the menisci transmits the majority of the load from the femur to the tibia

Question 16

what does the menisci secondarily provide

Answer 16

restraint to anterior laxity

Question 17

menisci improves stability by

Answer 17

increasing congruency of the tibiofemoral knee joint

increasing concavity of the tibial plateaus

increasing the articular surface area

Question 18

lubrication and nutrition

Answer 18

the menisci act as buffers b/w the tibia and the femur

reduce the coefficient of friction b/w the joint surfaces

Question 19

what helps lubricate the knee joint surfaces

Answer 19

triangular shape of the menisci

directing synovial fluid from the periphery to central portion of the joint

Question 20

shock absorption

Answer 20

menisci will help distribute weight bearing forces

responsible for 40-60% of the imposed load on the body

Question 21

pressure =

Answer 21

force / surface area

Question 22

normal gait forces on the knee

Answer 22

2-3x BW

Question 23

stairs and running forces on the knee

Answer 23

5-6x BW

Question 24

mobility

Answer 24

menisci will deform during flexion/extension and rotation of the knee joint

wedge shaped menisci will aide in the gliding of the articular surfaces

Question 25

in what direction will the menisci deform

Answer 25

opposite of the tibial plateaus same direction as the femur helps maintain joint congruity

Question 26

why do the menisci distort as opposed to truly moving

Answer 26

d/t various attachments of the menisci

Question 27

what happens during rotation

Answer 27

menisci follow the displacement of the femoral condyles

Question 28

during lateral tibial rotation

Answer 28

the lateral meniscus moves toward the anterior portion of the tibial plateau while the medial meniscus moves posteriorly meniscus follows displacement of the femoral condyles

Question 29

during flexion CKC

Answer 29

the femur must glide anteriorly the wedge shape of the menisci help to induce this anterior glide medial meniscus are pulled posterior by semimembranosus lateral meniscus is drawn posterior by popliteus tendon

Question 30

during extension

Answer 30

the demur must glide posteriorly wedge shape of the menisci help induce this posterior glide menisci are pulled anteriorly by the meniscopatellar ligament --> transmit tension generated by the quads

Question 31

which meniscus has more attachments

Answer 31

medial meniscus moves A-P 5-7 mm

Question 32

how much does the lateral meniscus move

Answer 32

11 mm

Question 33

vascularity

Answer 33

entire meniscus is well vascularized until 10-11 yrs old after, only the periphery is vascularized vascularity has treatment implications