Internal Oblique originates from which anatomical feature?

• A. Iliac Crest
• B. Ribs 5-12
• C. Lateral Epicondyle of Humerus
• D. Lateral Supracondylar Ridge of Humerus

Answer: (A)

The main idea is where the internal oblique attaches to start its action. The internal oblique originates from the iliac crest (and also from the thoracolumbar fascia and the inguinal ligament). From that pelvic anchor, its fibers run upward and medially to insert on the lower ribs and the linea alba, enabling trunk flexion, rotation, and abdominal compression. The iliac crest is the key origin here, which is why it’s the best choice.

Ribs used to be a point of insertion for the internal oblique, not its origin, and the other options refer to landmarks on the arm bones, which are unrelated to the abdominal muscles.