Core & AbdominalSource-checked

Transversus abdominis

Pronunciation: trans-VER-sus ab-DOM-ih-nis

For beginners

Picture a corset wrapping around your waist — that is the transversus abdominis. It does not bend the trunk; it tightens around it to stiffen and protect the spine, especially right before you lift something.

Show the advanced explanation

Because its fibers run circumferentially rather than up-down, it does not produce trunk flexion or rotation; its main role is raising intra-abdominal pressure to create a rigid cylinder that supports the spine under load.

Structure & function

Location: The deepest abdominal muscle, with fibers running horizontally around the trunk like a natural weight belt.
Origin: Iliac crest, inguinal ligament, and lower rib cartilages.
Insertion: Linea alba (abdominal midline).
Main action(s): Compresses the abdominal contents (draws the belly wall inward), increasing intra-abdominal pressure and helping stabilize the spine.
Joint(s) crossed: None directly (a compressor, not a mover of a specific joint); contributes to spinal stability indirectly.
Movement plane: —
Innervation: Intercostal nerves (T7–T12) and the iliohypogastric/ilioinguinal nerves
In daily movement: Bracing the trunk before lifting something, coughing, or straining.
In exercise: The key muscle behind a 'brace' cue; heavily active in planks and anti-rotation exercises like the Pallof press.
Commonly confused with: Confused with 'the abs' generally, but unlike the rectus abdominis it cannot be seen and does not curl the trunk.
Common misconceptions: 'Sucking in the stomach' is not the same as a proper brace — a functional brace stiffens the whole trunk, not just the front.

Exercises that use this muscle

As a primary mover

As a secondary / stabilizer

Pallof Press (secondary)
Bird-dog hold (secondary)

⚠ Safety note

Learning to brace correctly (rather than only sucking in) is a foundational safety skill before lifting heavier loads.

Sources

“The transversus abdominis compresses the abdominal cavity, increasing intra-abdominal pressure.”

Anatomy and Physiology 2e — OpenStax, Rice University · Ch. 11.3 Axial Muscles of the Abdominal Wall, and Thorax

Peer-reviewed textbook · License: CC BY-NC-SA 4.0 · Last checked 2026-07-19

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