anterior thigh: extensor of legs

Question 1

vastus medialis

Answer 1

• origin: intertrochanteric line medial lip of the linea aspera
• insertion: medial border of quadriceps tendon, some inferior fibers directly onto medial side of patella
• action: extends leg at knee joint

Question 2

vastus lateralis

Answer 2

• origin: greater trochanter, intertrochanteric line, lateral lip of the linea aspera
• insertion: lateral patella and RF ligament forming quads tendon
• action: extends leg

Question 3

vastus intermedius

Answer 3

• origin: proximal femoral shaft
• insertion: posterior surface of upper border of patella forming part of quadriceps tendon
• action: extends leg

Question 4

rectus femoris

Answer 4

• origin: straight head: anterior inferior iliac spine; reflected head: above the superior rim of the acetabulum
• insertion: patella and tibial tuberosity (via the patellar ligament)
• action: extends leg, flexes thigh

Question 5

quadriceps femoris

Answer 5

• origin: anterior surface of the femur and the anterior side of the medial and lateral intermuscular septa
• insertion: tibial tuberosity via the patellar ligament
• action: extends the knee; rectus femoris flexes the thigh