The internal oblique
Internal oblique · musculus obliquus internus abdominis
The middle side abdominal muscle, working with the external oblique to twist the trunk.
What it does
The internal oblique lies under the external oblique, its fibres running at right angles to it. When you twist to the right, your left external oblique and right internal oblique work together. It also helps compress the abdomen.
Surprising fact
The crossing fibre directions of the three flat abdominal muscles create a natural corset, like layers of plywood.
Why it matters
Strong obliques help you rotate powerfully and control twisting, protecting the lower back during lifting and sport.
Nearby
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Sources
Drafted with AI help; awaiting a human fact-check against these sources.
Open in the 3D atlas · Suggest a correction · Not medical advice.
3D models: Z-Anatomy & BodyParts3D (CC BY-SA 4.0 / 2.1 JP). Card text CC BY 4.0.