| Latin | Musculus obliquus externus abdominis |
|---|---|
| Origin |
|
| Insertion |
|
| Action |
|
| Nerve | Thoracoabdominal nerves and subcostal nerve (T7–T12) |
| Name | Latin obliquus, 'slanting' — its fibres run diagonally, like hands in the front pockets of a jacket. |
Palpation
- Client supine with a bolster under the knees, or side-lying for easier access to the waist.
- Place a flat hand on the side of the waist, between the lower ribs and the iliac crest.
- Feel the diagonal fibres running downwards and forwards, from the lower ribs towards the midline and the front of the pelvis.
- Ask the client to reach one hand across the body towards the opposite knee (flexion with rotation to the opposite side); the external oblique on the side the reaching shoulder comes from tightens under your hand.
The external oblique is the largest and most superficial of the three flat muscles of the abdominal wall. It covers the side of the waist, with the Internal oblique and Transversus abdominis below it. Its fibres run in the same direction as the external intercostals above it: downwards and forwards, like your fingers when you put your hands in your front pockets.
For rotation, the external oblique works as a team with the opposite internal oblique. Turning the trunk to the left uses the right external oblique and the left internal oblique. Side-bending uses the external and internal obliques on the same side, together with Quadratus lumborum.
Use gentle pressure over the abdomen. Broad effleurage and kneading along the waist between the ribs and the Iliac crest are usually well received. When you stroke across the whole abdomen, work clockwise (as you look down at the abdomen), following the colon up the client’s right side, across, and down the left side.