The Knee

Question 1

functions of the knee

Answer 1

support body weight
transmit forces between tibia and fibula
mobility

Question 2

what type of joint is the tibiofemoral joint?

Answer 2

synovial, bicondylar joint between the femoral condyles and tibial articular surfaces

Question 3

which of the tibia and femoral condyles are covered in cartilage?

Answer 3

femoral condyle covered in hyaline cartilage

Question 4

where do menisci in the tibiofemoral joint sit?

Answer 4

on top of the tibial condyles
they are semi-lunar fibrocartilage discs

Question 5

function of menisci

Answer 5

increased congruence between articular surfaces
assist weight bearing across joint
shock absorbers
facilitate accessory movements (sliding of bones)

Question 6

which ligaments are involved in the knee?

Answer 6

medial collateral ligament
lateral collateral ligament
anterior cruciate ligament
posterior cruciate ligament

Question 7

which of the ligaments are intracapsular and which are extracapsular?

Answer 7

extracapsular- MCL, LCL
intracapsular- ACL, PCL

Question 8

role of MCL

Answer 8

prevent valves displacement (knocking knees)

Question 9

role of LCL

Answer 9

prevent virus displacement (bowed legs)

Question 10

role of ACL

Answer 10

prevents anterior tibial displacement (lower leg comes forward)

Question 11

role of PCL

Answer 11

prevents posterior tibial displacement (lower leg moves backwards)

Question 12

what type of joint is the patellofemoral joint

Answer 12

synovial saddle joint between patella and patella surface of femur

Question 13

what type of bone is the patella?

Answer 13

sesamoid as embedded in quadriceps tendon

Question 14

function of patella

Answer 14

anatomic pulley allowing the quads to move around a corner
reduces friction between quadriceps tendon and femoral condyles

Question 15

structure of patella

Answer 15

sesamoid bone embedded in the quadriceps tendon
oval shaped and cartilage covered
a vertical ridge separates medial and lateral areas

Question 16

movements of patella

Answer 16

moves distally in flexion
moves proximally in extension

Question 17

what axes and planes does the knee move in?

Answer 17

bi-axial joint
flexion and extension occur about horizontal axis in sagittal plane
medial and lateral rotation occur about vertical axis in transverse plane

Question 18

what is the closest-packed position?

Answer 18

occurs at full extension of the knee
no rotation possible in this position
ligaments become taught
femur must medially rotate to get into locking position
unlocked by muscle activity of the popliteus muscle

Question 19

knee flexor muscles

Answer 19

bicep femoris
semimembranosus
semitendinosus
sartorius
gracilis

Question 20

knee extensor muscles

Answer 20

rectus femoris
vastus lateralis
vastus medialis
vastus intermedius
tensor fascia latae

Question 21

knee medial rotators

Answer 21

semimembranosus
semitendinosus
sartorius
gracilis

Question 22

knee lateral rotators

Answer 22

biceps femoris

Question 23

popliteus: origin, insertion, innervation, action

Answer 23

origin: lateral condyle of femur
inserts: medial surface of tibia
innervation: tibial nerve
action: internal rotation as it flexes

Question 24

biceps femoris: origin, insertion, innervation, action

Answer 24

origin: long head at ischial tuberosity
short head at lines aspera
insertion: head of fibula and lateral condyle of tibia
innervation: sciatic nerve
action: flexion, external rotation (extension and external rotation of hip)

Question 25

semimembranosus: origin, insertion, innervation, action

Answer 25

origin: ischial tuberosity inserts: media tibial condyle innervation: sciatic nerve action: flexion, internal rotation (extension and internal rotation of hip)

Question 26

semitendinosus: origin, insertion, innervation, action

Answer 26

origin: ischial tuberosity inserts: anterior medial surface of tibia innervation: sciatic nerve actions: flexion, external rotation (extension and external rotation of hip)

Question 27

sartorious: origin, insertion, innervation, action

Answer 27

origin: ASIS inserts: medial side of proximal tibia innervation: femoral nerve actions: flexion, internal rotation

Question 28

gracilis: origin, insertion, innervation, action

Answer 28

origin: pubis and inferior pubic ramus inserts: tibia innervation: obturator nerve movement: flexion, internal rotation

Question 29

rectus femoris: origin, insertion, innervation, action

Answer 29

origin: anterior inferior iliac spine inserts: superior aspect of patella innervation: femoral nerve action: extension (flexion of hip)

Question 30

vastus lateralis: origin, insertion, innervation, action

Answer 30

origin: greater trochanter inserts: patella innervation: femoral nerve action: extension

Question 31

vastus intermedius: origin, insertion, innervation, action

Answer 31

origin: femur inserts: patella innervation: femoral nerve action: extension

Question 32

vastus medialis: origin, insertion, innervation, action

Answer 32

origin: linea aspera inserts: patella innervation: femoral nerve action: extension

Question 33

tensor fascia latae: origin, insertion, innervation, action

Answer 33

origin: lateral side of iliac crest inserts: iliotibial band innervation: superior gluteal nerve action: extension, external rotation (hip internal rotation and abduction)