The |internal oblique| is a small, thin, deep muscle of the abdomen. It runs diagonally opposite underneath the |external obliques|. It has a quadrilateral form which extends from the hip bone (crest of the ilium) to the ~cartilage~ of the lower |ribs| (the seventh, eighth, and ninth |ribs|). This muscle protects a weak point in the |abdominal wall| and works with the |external oblique| to help twist the torso.
