Posterior Abdominal Muscles

Question 1

Which muscle is said to form the iliolumbar ligament?

Answer 1

quadratus lumborum

Question 2

What osseous part of the vertebral column serves as an origin to the quadratus lumborum?

Answer 2

transverse process of L5

Question 3

What non-vertebral column site serves as an origin to the quadratus lumborum?

Answer 3

iliac crest of the innominate bone

Question 4

What is the insertion of the quadratus lumborum?

Answer 4

transverse tubercle of the transverse process of L1-L4 and 12th rib

Question 5

Contraction of the quadratus lumborum will result in what movements?

Answer 5

• steadies the origin of the diaphragm
• when pelvis is fixed, it will laterally flex the lumbar spine
• bilaterally acts to extend the lumbar spine
• stabilizes and depresses the 12th rib

Question 6

What will innervate the quadratus lumborum?

Answer 6

ventral rami of T12 and L1-L3 or L4 spinal nerves

Question 7

What is the origin of the psoas major?

Answer 7

vertebral bodies of T12, L1-L5, S1 and transverse processes of L1-L5

Question 8

What is the insertion of the psoas major?

Answer 8

lesser trochanter of the femur

Question 9

Contraction of the psoas major will result in what movements?

Answer 9

• flex the thigh at the hip when the spine is stabilized
• flex trunk and tilt pelvis forward when thigh is stabilized
• important in raising body from supine to sitting positions

Question 10

What will innervate the psoas major?

Answer 10

primarily the ventral rami of L2 and L3, may include ventral rami of L1 and L4 spinal nerves

Question 11

What is the origin of the psoas minor?

Answer 11

vertebral bodies of T12 and L1

Question 12

What is the insertion of the psoas minor?

Answer 12

iliopubic eminence of the innominate bone

Question 13

Contraction of the psoas minor will result in what movements?

Answer 13

weakly flexes the trunk

Question 14

What will innervate the psoas minor?

Answer 14

ventral ramus of L1 spinal nerve

Question 15

What osseous part of the vertebral column serves as an origin to the iliacus?

Answer 15

superolateral margin of sacrum

Question 16

What non-vertebral column site serves as an origin to the iliacus?

Answer 16

• iliac crest

- upper 2/3 of the iliac fossa of the innominate bone

Question 17

What is the insertion of the iliacus?

Answer 17

lesser trochanter of femur

Question 18

Contraction of the iliacus will result in what movements?

Answer 18

• flex the thigh at the hip when the spine is stabilized
• flex the trunk and tilt pelvis forward when thigh is stabilized
• important in raising body from supine to standing positions

Question 19

What will innervate the iliacus?

Answer 19

the femoral nerve, primarily the ventral rami of L2 and L3