knee Flashcards Preview

Z MD1 Hip and leg anatomy > knee > Flashcards

Flashcards in knee Deck (32):
1

2 joints of the knee

tibiofemoral patellofemoral

2

movements of the knee joint

flexion-extension rotation (during flexion only)

3

why is there no rotation of the knee during extension

because the ligaments of the knee are tight and wont allow rotation

4

what is the close packed position of the knee

extension (most stable)

5

3 support structures of the knee

cruciate ligaments collateral ligaments menisci

6

explain the shape of the articular surfaces of the femur

medial condyle is longer than lateral lateral condyle is wider than medial

7

what is the function of the notch in the intracondylar space of the femur

where the anterior cruciate ligament lies

8

explain the movement of the femur on the tibia during extension

the femur orates medially on the fixed tibia during the last 15-20 degrees of extension around tight ACL (passive screw-home mechanism)

9

explain the movement of the femur on the tibia during flexion

femur rotates laterally on the fixed tibia - requires active contraction of popliteus muscle

10

what are the structures that are enclosed in the knee joint capsule

- menisci - cruciate ligaments (intracapsular but extrasynovial) - synovial membrane - synovidal fluid

11

what are the anterior reinforcements of the capsule of the knee

the patellar tendon and retinacular fibres

12

what are the lateral reinforcements of the capsule of the knee

popliteus muscle biceps femoris muscle iliotibial tract

13

what is the medial reinforcement of the capsule of the knee

pes anserinus tendons

14

what is the posterior reinforcement of the capsule of the knee

oblique popliteal ligament

15

what are the muscle insertions of the pes anserinus tendons reinforcing the knee joint capsule

sartorius gracilis bursa semiTendinosus "Say Grace Before Tea"

16

explain the deficiencies in the knee joint capsule

2 deficiencies: - above patella for suprapatellar bursa - posteriorly for popliteus tendon and semimembranousus bursa

17

attachments of the ACL

from the anterior part of the tibia to the lateral condyle of the femur

18

attachments of the PCL

from the posterior tibia up to the medial condyle of the femur

19

functions of the ACL

(passively rotates lateral condyle in medial direction) - stops the tibia from being displaced anteriorly from the femur or the femur being displaced posteriorly from the tibia - assists internal rotation of the femur - contributes to locking in extension

20

function of the PCL

stops the femur from sliding forwards off the tibial plateau during extension and stops posterior displacement of the tibia during flexion

21

how does ACL injury occur

when rotation occurs laterally (opposite direction) during extension on a weight bearing leg

22

how does PCL injury occur

- fall on flexed knee - bumper bar impact

23

function of medial collateral ligament

- resists abduction forces of the knee and lateral rotation of the tiba - limits anterior displacement of the tibia when ACL damaged

24

why is it that when the medial collateral ligament is damaged you often get damage to the medial meniscus

because the medial collateral ligament deep fibres attach to the medial meniscus

25

how does MCL injury occur

usually with a rotational injury with a force in a lateral direction

26

function of lateral collateral ligament

resists adduction forces (movement medially of the tiba in respect to the femur)

27

why is the LCL not as often damaged compared to the MCL

because it is separated from the joint by the tendon of popliteus

28

function of the menisci of the knee joint

- shock absorb - weight distribution

29

why is the medial meniscus more commonly injured compared to the lateral

- attachment to MCL - longer - horns are further apart - less mobile

30

what is the normal alignment of the patellofemoral joint maintained by

- vastus medialis muscle (active) - medial patellar retinaculum (passive) - raised lip on lateral femoral condyle (passive)

31

how does dislocation of the patella occur

patella pulled laterally by the strong quadriceps muscle

32

how does chondromalacia patella predispose to subluxation/dislocation of the patella

because there is a mechanical problem of tracking of the patella in the femoral groove due to degeneration of cartilage