internal oblique muscle

Introduction

Flat muscle of the anteroabdominal wall.

Origin

• iliac fascia deep to the lateral part of the inguinal ligament
• anterior 1/2 of the iliac crest
• lumbar fascia

Insertion

• 10th to 12th ribs
• aponeurosis contributes to sheath of rectus abdominis
• some of the fibers from the inguinal ligament terminate in the conjoint tendon

Action

• diminishes capacity of abdomen
• flexes lumbar vertical column (bends thorax forward)

Innervation

• lower thoracic nerve

More general terms

• skeletal muscle (voluntary muscle)