Abdominal Wall Muscles

Question 1

Name the 5 muscles of the posterior abdominal wall

Answer 1

Iliacus, psoas major, psoas minor, quadratus lumborum and the diaphragm

Question 2

Origin and attachments of the quadratus lumborum

Answer 2

Origin- Iliac crest and iliolumbar ligament

Attachment- Transverse process of L1-4 and the inferior border of 12th rib

Question 3

Action of quadratus lumborum

Answer 3

Extension and lateral flexion of the vertebral column

Fixes 12th rib during inspiration

Question 4

Innervation of quadratus lumborum

Answer 4

Anterior rami of T12-L4 nerves

Question 5

Origin and attachments of psoas major

Answer 5

Origin- Transverse process and vertebral bodies of T12-L5

Attachments- Lesser trochanter of femur

Question 6

Actions of psoas major

Answer 6

Flexion of the thigh at the hip and lateral flexion of the vertebral column

Question 7

Innervation of psoas major

Answer 7

Anterior rami of L1-3 nerves

Question 8

Origin and attachments of psoas minor

Answer 8

Origin- Vertebral bodies of T12 and L1

Attachment- Superior ramus of the pubic bone

Question 9

Actions of psoas minor

Answer 9

Flexion of the vertebral column

Question 10

Innervation of psoas minor

Answer 10

Anterior rami of L1 spinal nerve

Question 11

Origin and attachments of iliacus

Answer 11

Origin- Iliac fossa and anterior inferior iliac spine

Attachment- Combines with tendon of the psoas major and inserts at lesser trochanter of the femur

Question 12

Actions of iliacus

Answer 12

Flexion and lateral rotation of the thigh at the hip

Question 13

Innervation of iliacus

Answer 13

Femoral nerve (L2-4)

Question 14

What is iliopsoas?

Answer 14

Combination of iliacus and psoas major which acts as the major flexor of the thigh

Question 15

Name the 3 flat muscles of the abdominal wall

Answer 15

External oblique, internal oblique, transversus abdominis

Question 16

Origin and attachment of external oblique

Answer 16

Origin- Ribs 5-12

Attachment- Iliac crest and pubic tubercle

Question 17

Function of external oblique

Answer 17

Contralateral rotation of the torso

Question 18

Innervation of external oblique

Answer 18

Thoracoabdominal nerves (T7-11) and subcostal nerve (T12)

Question 19

Origin and attachment of internal oblique

Answer 19

Origin- Inguinal ligament, iliac crest and lumbodorsal fascia
Attachment- Ribs 10-12

Question 20

Function of internal oblique

Answer 20

Compression and rotation of the torso

Question 21

Innervation of internal oblique

Answer 21

Thoracoabdominal nerves (T7-T11), subcostal nerve (T12) and branches of the lumbar plexus

Question 22

Origin and attachment of transversus abdominis

Answer 22

Origin- Inguinal ligament, costal cartilages 7-12, the iliac crest and thoracolumbar fascia
Attachment- Conjoint tendon, xiphoid process, linea alba and the pubic crest

Question 23

Function of transversus abdominis

Answer 23

Compression of abdomen

Question 24

Innervation of transversus abdominis

Answer 24

Thoracoabdominal nerves (T7-T11), subcostal nerve (T12) and branches of the lumbar plexus

Question 25

Fibre direction of external obliques

Answer 25

Inferomedially

Question 26

Fibre direction of internal obliques

Answer 26

Superomedially

Question 27

Fibre direction of transversus abdominis

Answer 27

Transversely

Question 28

Name the 2 vertical muscles in the abdominal wall

Answer 28

Rectus abdominus and pyramidalis

Question 29

What line splits the rectus abdominis into 2

Answer 29

Linea alba

Question 30

Which lines mark the boundaries of the rectus abdominis

Answer 30

Linea semilunaris

Question 31

Attachment and origin of rectus abdominis

Answer 31

Origin- Pubic crest | Attachment- Xiphoid process, costal cartilage 5-7

Question 32

Function of rectus abdominis

Answer 32

Compression of the abdomen, stabilising the pelvis during walking and depressing the ribs

Question 33

Innervation of rectus abdominis

Answer 33

Thoracoabdominal nerves (T7-11)

Question 34

Attachment and origin of pyramidalis

Answer 34

Origin- Pubic crest and pubic symphis | Attachment- Linea alba

Question 35

Function of pyramidalis

Answer 35

Tense the linea alba

Question 36

Innervation of pyramidalis

Answer 36

Subcostal nerve (T12)