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. By TeachMeSeries Ltd (2025) Fig 1Lateral view of the abdominal wall. The internal oblique is visible – note that its fibres are perpendicular to those of the external oblique. Pro Feature - 3D Model You've Discovered a Pro Feature Access our 3D Model Library Explore, cut, dissect, annotate and manipulate our 3D models to visualise anatomy in a dynamic, interactive way. Learn More Pro Feature - Dissection Images Dissection of the anterolateral abdominal wall Dissection of the anterolateral abdominal wall You've Discovered a Pro Feature Access our Dissection Image Library Enhance your understanding with high-resolution dissection images showcasing real-life anatomy. Learn More Print Article Rate This Article