The Probert Encyclopaedia of Medicine

INTERNAL OBLIQUE

The internal oblique (obliquus internus abdominis) is a small, thin, deep muscle of the abdomen. It runs diagonally opposite underneath the external oblique. It has a quadrilateral form originating from the hip bone (crest of the ilium), and extending to the cartilage of the lower ribs (the tenth, elenenth, and twelfth ribs). It is innervated by the lower thoracic nerves and supplied the intercostal and lumbar arteries. This muscle protects a weak point in the abdominal wall and works with the external oblique to help twist the torso.
Research Internal Oblique