Internal abdominal oblique muscle
Musculus obliquus internus abdominis
Definition
The internal abdominal oblique is a flat, sheet-like muscle that lies deep to the external abdominal oblique and superficial to the transversus abdominis. It arises from the thoracolumbar fascia and the tuber coxae, and its fibers generally run cranioventrally, perpendicular to those of the external oblique.
Origin: Thoracolumbar fascia and tuber coxae.
Insertion: The aponeurosis on the linea alba and the fleshy ending on the thirteenth rib and cartilage of the twelfth rib.
Action: Compression and support of the abdominal viscera.
Nerve: Medial branches of the last few intercostales and costoabdominalis, iliohypogastricus and ilioinguinalis nerves.
References
Miller's Anatomy of the Dog 4th Edition
