The external oblique abdominis is an oblique muscle in the abdominal region, located laterally and anteriorly. It extends from the ribs to the iliac crest and is connected to the rectus abdominis by the rectus sheath. The external oblique is primarily responsible for rotation and lateral flexion of the spine. In addition, it contributes to abdominal compression and plays a role in activities such as lateral bending and twisting.