abdominal oblique muscle

The abdominal oblique muscle (oblique abdominal muscle) refers collectively to either the external or internal abdominal oblique muscles — two of the flat muscles forming the lateral abdominal wall. These muscles run diagonally and provide trunk stability and rotational movement.

Abdominal oblique muscles are situated on the lateral and anterolateral walls of the abdomen. The external oblique is the most superficial, while the internal oblique lies immediately deep to it. Both span from the ribs and thoracolumbar fascia down to the iliac crest and inguinal ligament.

Abdominal oblique muscles flex and rotate the trunk, compress the abdominal contents, assist with lateral bending, and help maintain intra-abdominal pressure. Their combined action with the transversus abdominis forms the core muscular corset that stabilizes the spine.

Oblique muscle strains are common in sports requiring twisting motions. Weakness in these muscles can contribute to lumbar spine instability and chronic back pain. Inguinal hernias may develop where the oblique aponeuroses form the inguinal canal.

The external oblique is superficial to the internal oblique, and their muscle fibers run in opposite diagonal directions. This arrangement creates a mechanically advantageous structure where the two muscles act synergistically to resist forces from multiple directions.