Anterior Thigh Muscles: Flexors of Hip & Extensors of Knee

Question 1

Rectus Femoris (Quadriceps)
(Extensor of knee)

Answer 1

O: Anterior inferior iliac spine and ilium superior to acetabulum

I: Base of patella and to tibial
tuberosity via patellar ligament

I: Femoral nerve (L2, L3, L4)

B: Profunda femoris and lateral circumflex
femoral arteries

A: Extends leg at knee joint and flexes
thigh at hip joint

Question 2

Vastus Lateralis (Quadriceps)
(Extensor of knee)

Answer 2

O: Greater trochanter, lateral lip of linea aspera of femur

I: Base of patella and to tibial
tuberosity via patellar ligament

I: Femoral nerve (L2, L3, L4)

B: Lateral circumflex femoral and profunda femoris arteries

A: Extends leg at knee joint

Question 3

Vastus medialis (quadriceps)
(Extensor of knee)

Answer 3

O: Intertrochanteric line, medial lip of linea aspera of femur

I: Base of patella and to tibial
tuberosity via patellar ligament

I: Femoral nerve (L2, L3, L4)

B: Femoral and profunda
femoris arteries

A: Extends leg at knee joint

Question 4

Vastus intermedius (quadriceps)
(Extensor of knee)

Answer 4

O: Anterior and lateral surfaces of body of femur

I: Base of patella and to tibial
tuberosity via patellar ligament

I: Femoral nerve (L2, L3, L4)

B: Lateral circumflex femoral and profunda femoris arteries

A: Extends leg at knee joint

Question 5

Pectineus

Flexor of hip

Answer 5

O: Superior ramus of pubis

I: Pectineal line of femur

I: Femoral nerve and sometimes obturator nerve

B: Medial circumflex femoral artery, obturator artery

A: Adducts and flexes thigh at hip

Question 6

Psoas major (Iliopsoas)
(Flexor of hip)

Answer 6

O: Transverse processes of lumbar vertebrae, sides of bodies of T12–L5 vertebrae, intervening intervertebral discs

I: Lesser trochanter of femur

I: Ventral rami of first lumbar nerve (L1-L3)

B: Lumbar branches of iliolumbar artery

A: Acting superiorly with iliacus, flexes hip; acting inferiorly, flexes vertebral column laterally; used to balance trunk in sitting position; acting inferiorly with iliacus, flexes trunk

Question 7

Iliacus (Iliopsoas)

Flexor of Hip

Answer 7

O: Superior 2/3 of iliac fossa, iliac crest, ala of sacrum, anterior sacro-iliac ligaments

I: Lesser trochanter of femur and shaft
inferior to it, to psoas major tendon

I: Femoral nerve

B: Iliac branches of iliolumbar artery

A: Flexes thigh at hips and stabilizes hip joint, acts with psoas major

Question 8

*Psoas minor

Flexor of hip

Answer 8

O: Vertebral margins of T12–L1
vertebrae, corresponding intervertebral disc

I: Pectineal line, iliopectineal
eminence

I: Ventral rami of first lumbar nerve

B: Lumbar branch of iliolumbar artery

A: Flexes pelvis on vertebral column

Question 9

Sartorius

Flexor of hip

Answer 9

O: Anterior superior iliac spine and superior part of notch below it

I: Superior part of medial surface of tibia

I: Femoral nerve

B: Femoral artery

A: Abducts, laterally rotates, and flexes thigh;
flexes knee joint