Structures

  • External oblique
  • Internal oblique
  • Transversus abdominus
  • Rectus abdominus
  • Pyramidalis

MuscleActionOriginInsertionInnervationBlood supply
External oblique- Compress abdominal cavity
- Rotate trunk to opposite side
- Weak flexion of lumbar spine
- Aid expiration by compressing lower thoracic cage
- Lateral surfaces of the lower eight ribs (ribs 5 to 12)- Lateral iliac crest
- Aponeurosis to end at linea alba (midline raphe)
- Anterior rami of T7-12 thoracic spinal nerves - Lower posterior intercostal and subcostal arteries
- Superior and Inferior epigastric arteries
- Superficial and deep circumflex iliac arteries
- Posterior lumbar arteries
Internal oblique- Compress abdominal cavity
- Rotates trunk to same side
- Weak flexion of lumbar spine
- Thoracolumbar fascia
- Iliac crest
- Lateral 2/3 of inguinal ligament
- Inferior border of the lower 3-4 ribs
- Aponeurosis which ends in linea alba;
- Pubic crest
- Anterior rami of T7-T12 thoracic spinal nerves and L1- Lower posterior intercostal and subcostal arteries
- Superior and Inferior epigastric arteries
- Superficial and deep circumflex iliac arteries
- Posterior lumbar arteries
Transversus abdominis- Compress abdominal cavity- Thoracolumbar fascia
- Medial iliac crest
- Lateral 1/3 of inguinal ligament
- Costal cartilages of ribs 7-12
- Aponeurosis which ends in linea alba
- Pubic crest
- Anterior rami of T7 to T12 and L1- Lower posterior intercostal and subcostal arteries
- Superior and Inferior epigastric arteries
- Superficial and deep circumflex iliac arteries
- Posterior lumbar arteries
Rectus abdominis- Compress abdominal cavity
- Flex lumbar spine
- Pubic crest- Costal cartilages of ribs 5-7;
- Anterior rami of T7-T12- Superior epigastric artery
- Inferior epigastric artery
- Superficial epigastric artery
Pyramidalis- Tenses the linea alba- Anterior pubis and pubic symphysis- Linea alba- Anterior ramus of T12- Inferior epigastric artery
- Superficial epigastric artery