knee

Question 1

what is the knee joint?

Answer 1

• synovial joint
• connects femur, tibia and fibula

Question 2

what are the functions of the knee?

Answer 2

• supports body weight
• transmits force to provide movement
• stability
• mobility

Question 3

what movement occurs at the knee and their angles

Answer 3

flexion (140) extension (0) medial (25) and lateral (40) rotation

Question 4

what is the joint between femur and tibia?

Answer 4

tibiofemoral

Question 5

describe tibiofemoral joint

Answer 5

synovial bicondylar joint between femoral condyles and tibia

Question 6

what movement is allowed in tibiofemoral joint?

Answer 6

• movement in two planes around two axes as bi- axial

Question 7

where are the femoral condyles and describe appearance

Answer 7

• distal end of femur
• covered in hyaline cartilage

Question 8

what condyle is longer? what shapes are they?

Answer 8

• lateral profile longer than medial
• convex so like a circle

Question 9

where are the tibia condyles found?

Answer 9

• proximal end of tibia

Question 10

what are the tibia condyles covered by?

Answer 10

• cartilage layer
• menisci

Question 11

describe medial surface of tibia condoyle

Answer 11

• large
• oval

Question 12

describe lateral surface of tibia condyle

Answer 12

• smaller
• circular

Question 13

what are menisci?

Answer 13

• fibrocartilage discs
• semi lunar

Question 14

what are the four functions of knee menisci

Answer 14

• increases congruency between articular surfaces
• absorbs shock
• assists weight bearing across joint (transfers/ absorbs)
• facilitates accessory movements

Question 15

what is the medial collateral ligament?

Answer 15

extra-capsular ligament that is a broad flat band,10cm long

Question 16

where does medial collateral ligament originate and insert?

Answer 16

origin= medial epicondyle of femur
insert= tibia condyle

Question 17

what does medial collateral ligament prevent?

Answer 17

• valgus displacement, whereby knee knock position= adduction of a joint that doesn’t usually adduct

Question 18

what is lateral collateral ligament?

Answer 18

extra capsular, strong short thin cord

Question 19

what is lateral collateral ligament origin and insertion?

Answer 19

origin= lateral epicondyle of femur
insert= head of fibula

Question 20

what does the lateral collateral ligament prevent?

Answer 20

varus displacement= bow legged action; adduction when not meant to

Question 21

what is the anterior cruciate ligament?

Answer 21

intracapsular ligament that crosses over and splits into two bundles

Question 22

where does anterior cruciate ligament originate and insert?

Answer 22

origin= posteromedial surface of lateral femoral condyle
insert= anterolateral tibial spine

Question 23

what does anterior cruciate prevent?

Answer 23

anterior tibial displacement whereby tibia moves forwards onto femur

Question 24

what is the posterior cruciate ligament ?

Answer 24

intracapsular ligament that splits into two bundles

Question 25

what is the origin and insertion of posterior cruciate ligament?

Answer 25

origin= anterolateral surface of medial femoral condyle insert= posterior intercondylar area

Question 26

what does posterior cruciate ligament prevent?

Answer 26

posterior tibial displacement where something strikes front of knee and pushes tibia back

Question 27

what is the name of the joint between patella and femur?

Answer 27

patellofemoral

Question 28

what type of joint is patellofemoral?

Answer 28

- synovial saddle as both have concave and convex parts

Question 29

what bone is the patella?

Answer 29

largest sesamoid bone in body - bone embedded in quadriceps tendon

Question 30

describe the patellar surface of femur

Answer 30

- cartilage covered surface - groove articulates with a ridge on patellar surface

Question 31

what are the functions of patella?

Answer 31

- reduces friction between quadriceps tendon and femoral condyles (less damage) - anatomic pulley as quadriceps can pull round corner to pull tibia and extend the knee

Question 32

what is the shape and colour of patella?

Answer 32

- oval shaped - shiny due to hyaline cartilage

Question 33

what separates medial and lateral areas ? - what is up and down sections? - what is superior to inferior?

Answer 33

vertical ridge; convex= up/ down concave= superior to inferior

Question 34

what area is larger?

Answer 34

lateral area

Question 35

where is quadriceps tendon?

Answer 35

- on top of patella

Question 36

where is patella tendon and where does it insert?

Answer 36

- below patella - inserts into tibial tuberosity and allows insertion of thigh muscles

Question 37

what is the patella tendon continuous with?

Answer 37

- quadricep femoris tendon

Question 38

what occurs during close packed position? give some properties

Answer 38

- extension as patella moves up proximally - no rotation allowed - stable and congruent due to maximum contact - ligaments become taut

Question 39

what does loose packed position allow?

Answer 39

- flexion as patella moves distally on femur - allows some rotation

Question 40

what is a joint capsule?

Answer 40

fibrous bag made of dense irregular connective tissue that holds synovial fluid

Question 41

what is the capsule reinforced by?

Answer 41

- number or ligaments and tendons e.g. collateral ligaments, expansions coming off quadriceps

Question 42

why is the knee classed as incomplete? what is it plugged by?

Answer 42

- hole at the front - plugged by patella and patella tendon

Question 43

what are bursaes?

Answer 43

fluid filled sacs to reduce friction e.g. skin doesn't rub on patella

Question 44

what does pes anserinus bursa stop?

Answer 44

- medial collateral ligament rubbing on three tendons

Question 45

what bursa is above patella and under quad femoris tendon?

Answer 45

-suprapatellar

Question 46

what bursa sits on top of patella?

Answer 46

prepatellar

Question 47

what bursa sits underneath patella tendon ?

Answer 47

intrapatellar

Question 48

what is the knee locking mechanism?

Answer 48

- femur rotates to complete movement i.e. in last 30 degrees of full extension femur medially rotates

Question 49

why does the knee locking mechanism occur?

Answer 49

- inequality of articular surface of femur condyles

Question 50

what happens during extension?

Answer 50

- tibia rolls posteriorly, elongates PCL and its pull on tibia causes it to glide anterior

Question 51

what happens during extension?

Answer 51

- tibia rolls anteriorly, elongates ACL and its pull so tibia glides posteriorly

Question 52

what occurs in unlocking?

Answer 52

- lateral rotation of femur - use of popliteus (back of knee)

Question 53

what is passive insufficiency?

Answer 53

muscle lengthened but limited movement at one/ more joints it crosses

Question 54

what is active insufficiency?

Answer 54

decreased tension and inability to generate force in multi- joint muscle when in shortened position as no binding sites free

Question 55

where do knee flexors sit?

Answer 55

- posterior

Question 56

where do knee extensors sit?

Answer 56

- anterior - above knee

Question 57

origin, insertion and action of gastrocnemius

Answer 57

o- femoral condyles I- posterior calcaneus A- flexion lateral head goes to lateral condyle whereas medial head starts at medial condyle

Question 58

origin, insertion and action of biceps femoris

Answer 58

o- short head= Linea aspera; long= medial ischial tuberosity I- fibula head a- flexor and lateral rotator

Question 59

origin, insertion and action of sartorius

Answer 59

o -anterior superior iliac spine (ilium) I= pes anserinus a= flexor and medial rotator

Question 60

origin, insertion and action of rectus femoris

Answer 60

o- (long) anterior superior iliac spine (short) groove above acetabulum I= patella a= extensor

Question 61

origin, insertion and action of vastus lateralis

Answer 61

o= greater trochanter I= tendon of rectus femoris and patella A= extensor

Question 62

Insertion, origin and action of vastus medialis

Answer 62

I= medial line of Linea aspera and medial supracondylar line I= medial patella A= extensor

Question 63

Origin, insertion and action of vastus intermedius

Answer 63

O= upper anterior and lateral surface of femur I= rectus femoris tendon and base of patella A= extensor

Question 64

Origin, insertion and action of tensor fascia Lata

Answer 64

O= lateral anterior iliac crest I = iliotibial band A= extensor; stabilises knee

Question 65

Origin, insertion and action of semitendinosus

Answer 65

o= lower ischial tuberosity I= pes anserinus a= medial rotator

Question 66

Origin, insertion and action of semimembranosus

Answer 66

o= upper ischial tuberosity I= medial tibial condyle A= medial rotation

Question 67

Origin, insertion and action of gracilis

Answer 67

o= inferior pubic ramus I= pes anserinus A= medial rotation

Question 68

Origin, insertion and action of popliteus

Answer 68

o= lateral femoral condyle I=posterior tibia A= medial rotation

Question 69

what are the functions of popliteus ?

Answer 69

- pulls lateral meniscus backwards to stop it getting trapped in flexion -allows accessory movements; stability in joint capsule