The external oblique muscle is one of the largest parts of the human trunk. It is one of the outermost of the abdominal muscles, extending from the crest of the ilium to the pectorals. On one side, other abdominals cover the stomach, while towards the back, the external oblique comes close to the serratus muscles. The intercostal and subcostal nerves provide innervations as well a neural connection to the brain. The external obliques on either side not only help rotate the trunk, but they perform a few other vital functions. The muscle helps pull the chest, as a whole, downwards, which compresses the abdominal cavity. Although relatively minor in scope, the external oblique muscle also supports the rotation of the spine. Since the muscle contributes to many trunk movements, strain or injury to the muscle can be debilitating. This may include movements that do not directly use the muscle. For example, ambulatory motions such as walking or running cause slight movements in the torso.
Written and medically reviewed by the Healthline Editorial Team
In Depth: External oblique