key muscles of the knee (I and A)

Question 1

rectus femoris

Answer 1

origin: anterior inferior iliac spine
insertion: tibial tuberosity and patella
action: extends leg at the knee joint, flexes thigh at hip joint

Question 2

vastus medialis

Answer 2

origin: intertrochanteric line, pectineal line of femur
insertion: tibial tuberosity and patella
action: extends leg at knee joint

Question 3

vastus lateralis

Answer 3

origin: greater trochanter, intertrochanter line, greater trochanter, linea aspera of femur
insertion: tibial tuberosity, patella, lat condyle of tibia
action: extends leg at knee joint

Question 4

vastus intermedius

Answer 4

origin: ant surface of femoral shaft
insertion: tibial tuberosity, patella, medial condyle of tibia
action: extends leg at knee joint

Question 5

biceps femoris

Answer 5

origin long head: ischial tuberosity, sacrotuberous ligament
origin short head: linea aspera of femur, lateral supracondyle
insertion: head of the fibula
action: extends and external rotation of the thigh, leg flexion, external rotation of knee, pelvis stabilisation

Question 6

semitendinosus

Answer 6

origin: ischial tuberosity
insertion: proximal end of tibia below medial condyle
action: extension and internal rotation of thigh, knee flexion, internal rotation, stabilise pelvis

Question 7

semimembranosus