Lower Extremity Muscles

Question 1

Psoas Major

Answer 1

• L1-L3 spinal nerves
• O: T12-L4 bodies, L1-L5 transverse processes
• I: lesser trochanter
• A: flexion and adduction of hip

Question 2

Iliacus

Answer 2

• L2-L3, Femoral nerve
• O: Iliac Fossa
• I: Lesser Trochancter of Femur
• A: Hip Flexion, Adduction

Question 3

Psoas Minor

Answer 3

• L1-L2 spinal nerves
• O: T12 and L1 vertebral bodies
• I: Superior pubic ramus
• A: trunk flexion
• Only found in some of the population

Question 4

Pectineus

Answer 4

• L2 - L3 - L4, femoral nerve (possible obturator)
• O: superior pubic ramus
• I: distal to lesser trochanter of femur
• Thigh flexion and adduction

Question 5

Tensor Fascia Latae

Answer 5

• L4 - L5 - S1, superior gluteal nerve
• O: ASIS
• I: Iliotibial tract
• A: thigh abduction, flexion, and internal rotation

Question 6

Sartorius

Answer 6

• L2 - L3 - L4, femoral nerve
• O: ASIS
• I: Pes Anserinus
• A: thigh flexion, abduction, and external rotation

Question 7

Rectus Femoris

Answer 7

• L2 - L3 - L4, femoral nerve
• O: AIIS and acetabular rim
• I: patellar tendon
• A: hip flexion and knee extension

Question 8

Vastus Lateralis

Answer 8

• L2 - L3 - L4, femoral nerve
• O: greater trochanter, intertrochateric line, linea aspera
• I: patellar ligament
• A: knee extension

Question 9

Vastus Intermedius

Answer 9

• L2 - L3 - L4, femoral nerve
• O: anterior femur
• I: patellar ligament
• A: knee extension

Question 10

Vastus Medialis

Answer 10

• L2 - L3 - L4, femoral nerve
• O: intertrochanteric line, linea aspera
• I: patellar ligament
• A: knee extension

Question 11

Adductor Magnus

Answer 11

• Adductor part: L2 - L3 - L4, obturator nerve
• Hamstring part: L4, tibial nerve
• O
  
  • Adductor part: inferior pubic ramus
  • Hamstring part: ischial tuberosity
• I
  
  • Adductor part: linea aspera
  • Hamstring part: adductor tubercle of femur
• A
  
  • Adductor part: thigh flexion, adduction, external rotation
  • Hamstring part: thigh extension and internal rotation

Question 12

Adductor Longus

Answer 12

• L2 - L3 - L4, obturator nerve
• O: pubic tubercle
• I: linea aspera
• A: thigh flexion, adduction, and external rotation

Question 13

Adductor Brevis

Answer 13

• L2 - L3 - L4, obturator nerve
• O: inferior pubic ramus
• I: linea aspera
• A: flexion, adduction, external rotation

Question 14

Gracillis

Answer 14

• L2 - L3, obturator nerve
• O: inferior pubic ramus
• I: pes anserinus
• A: thigh flexion and adduction, knee flexion and internal rotation

Question 15

Gluteus Maximus

Answer 15

• L5 - S1 - S2, inferior gluteal nerve
• O: posterior ilium, lateral sacrum
• I: gluteal tuberosity of the femur and Iliotibial tract
• A: thigh extension, external rotation, abduction (superior part), adduction (inferior part)

Question 16

Gluteus Medius

Answer 16

• L4 - L5 - S1, superior gluteal nerve
• O: lateral ilium
• I: greater trochanter
• A: Thigh abduction
  
  • anterior fibers: thigh flexion and internal rotataion
  • posterior fibers: thigh extension and external rotation

Question 17

Piriformis

Answer 17

• S1 - S2, nerve to the piriformis
• O: lateral sacrum
• I: greater trochanter of the femur
• A: thigh external rotation, thigh abduction when flexed

Question 18

Obturator Internis

Answer 18

• L4 - L5 - S1, lumbosacral plexus, nerve to obturator internus
• O: obturator foramen
• I: medial greater trochanter of the femur
• A: thigh external rotation, thigh abduction when flexed

Question 19

Superior and Inferior Gemellus

Answer 19

• Superior: L5 - S1 - S2, lumbosacral plexus, nerve to obturator internus
• Inferior: L4 - L5 - S1, lumbosacral plexus, nerve to the quadratus femoris
• O:
  
  • Superior: Ischial Spine
  • Inferior: Ischial Tuberosity
• I: medial greater trochanter
• A: external rotation of the thigh, abduction when flexed

Question 20

Gluteus Minor