Full External Abdominal Oblique Muscle Description
[Continued from above] . . . and rotates it, bringing the shoulder of that side forward. The internal abdominal oblique muscle is also irregularly four-sided in form and lies under the external oblique muscle. Both sides, acting together, flex the vertebral column, drawing cartilage down toward the pubis. One side acting alone bends the vertebral column sideways, rotating it to bring the shoulder of the opposite side forward. Both of the abdominal oblique muscles work to compress abdominal contents, assist in the digestive process and in forced expiration.