Part of the TeachMe Series

Internal Oblique

star star star star star
based on 1 ratings

Original Author(s): Aren Mnatzakanian
Last updated: January 2, 2023
Revisions: 6

Original Author(s): Aren Mnatzakanian
Last updated: January 2, 2023
Revisions: 6

format_list_bulletedContents add remove
 

The internal oblique is a muscle of the anterior abdominal wall. It is a broad, sheet-like muscle, located deep to the external oblique.

  • Attachments: Originates from the inguinal ligament, iliac crest and lumbodorsal fascia. It inserts onto ribs 10-12.
  • Actions: Bilateral contraction compresses the abdomen, while unilateral contraction ipsilaterally rotates the torso.
  • Innervation: Thoracoabdominal nerves (T7-T11), subcostal nerve (T12) and branches of the lumbar plexus.
  • Blood supply: Lower posterior intercostal and subcostal arteries, superior and inferior epigastric arteries, superficial and deep circumflex arteries, posterior lumbar arteries.

    Fig 1 – Lateral view of the abdominal wall. The internal oblique is visible – note that its fibres are perpendicular to those of the external oblique.