Muscles of the Anterior Thigh

Question 1

Innervation (generally)

Answer 1

Femoral nerve (L2-L4)

Question 2

Action (generally)

Answer 2

Extend leg at the knee joint

Question 3

Muscles

Answer 3

Pectineus
Sartorius
Quadriceps femoris
End of iliopsoas

Question 4

Iliopsoas

Answer 4

2 muscles - psoas major and iliacus

• Origin - psoas major - lumbar vertebrae / iliacus - iliac fossa of pelvis
• Insertion - lesser trochanter of the femur
• Actions - flexes lower limb at the hip and assists lateral rotation at hip
• Innervation - psoas major - anterior rami of L1-3 / iliacus - femoral nerve

Question 5

Quadriceps Femoris

Answer 5

Vastus lateralis
Vastus intermedius
Vastus medialis
Rectus femoris

Question 6

Vastus lateralis

Answer 6

• Origin - greater trochanter and lateral lip of linea aspera
• Attachment - patella via patellar ligament
• Actions - extends knee joint and stabilises patella
• Innervation - femoral nerve

Question 7

Vastus intermedius

Answer 7

• Origin - anterior and lateral surfaces of the femoral shaft
• Attachment - patella via patellar ligament
• Actions - extends the knee joint and stabilises the patella
• Innervation - femoral nerve

Question 8

Vastus medialis

Answer 8

• Origin - intertrochanteric line and medial lip of the linea aspera
• Attachment - patella via patellar ligament
• Actions - extends knee joint, stabilises patella, particularly due to its horizontal fibres at the distal end
• Innervation - femoral nerve

Question 9

Rectus femoris

Answer 9

• Origin - ilium, just superior to the acetabulum
• Attachment - patella via the quadriceps tendon
• Actions - extends the knee joint, flexes the leg at the hip
• Innervation - femoral nerve

Question 10

Sartorius

Answer 10

• Origin - anterior superior iliac spine
• Attachment - superior, medial surface of the tibia
• Actions - flexor, abductor, and lateral rotator at the hip, flexes the knee
• Innervation - femoral nerve

Question 11

Pectineus

Answer 11

• Origin - pectineal line on the anterior surface of pelvis
• Attachment - pectineal line on posterior side of the femur, inferior to the lesser trochanter
• Actions - adduction and flexion at hip joint
• Innervation - femoral nerve (may receive a branch from obturator nerve)

Question 12

Testing quadriceps femoris

Answer 12

Suspected femoral nerve damage, quads can be tested
Ask patient to lie in supine position with knees slightly flexed -> ask patient to extend leg and resist the movement -> contraction of quads should be visible