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Core & AbdominalSource-checked

Rectus abdominis

Rectus abdominis

Pronunciation: REK-tus ab-DOM-ih-nis

Simplified front view of the abdomen showing the segmented rectus abdominis running down the midline, the diagonal external oblique on each side, and the transversus abdominis wrapping around the waist beneath.
Core region — rectus abdominis, obliques, and transversus abdominis (simplified). A beginner-level schematic of the core's abdominal muscles: rectus abdominis, external oblique, and transversus abdominis.
Illustration: Anatomy Learning Platform (original) · CC0-1.0 (public domain dedication)

For beginners

This is the muscle people mean by 'abs' — it runs down the front of your belly and curls your ribcage toward your pelvis, like a sit-up.

Show the advanced explanation

The tendinous intersections that create the 'six-pack' look are a structural feature, not separate muscles that can be trained individually — genetics and body-fat level, not exercise choice, mainly determine visibility.

Structure & function

Location
The long, paired muscle running down the front of the abdomen, popularly known as the 'six-pack' (the visible segments come from tendinous bands crossing it).
Origin
Pubic bone.
Insertion
Cartilage of ribs 5–7 and the xiphoid process.
Main action(s)
Flexes the vertebral column (curls the trunk forward), and compresses the abdomen.
Joint(s) crossed
Intervertebral joints of the lumbar and lower thoracic spine
Movement plane
sagittal
Innervation
Intercostal nerves (T7–T12)
In daily movement
Curling forward, such as sitting up from lying down, and bracing when coughing or straining.
In exercise
Prime mover in trunk-flexion exercises (crunches, sit-ups) and active isometrically in planks.
Commonly confused with
Often assumed to be 'the' core muscle; in reality the obliques and transversus abdominis are equally important for rotation and bracing.
Common misconceptions
'You can spot-reduce belly fat by training the rectus abdominis' is false — exercise builds/strengthens the muscle, but fat loss is a whole-body process.

Exercises that use this muscle

As a primary mover

As a secondary / stabilizer

⚠ Safety note

High-repetition spinal flexion (many crunches/sit-ups) under load can aggravate some low-back conditions; alternatives that limit spinal flexion exist for those cases.

Sources

“The rectus abdominis flexes the vertebral column and compresses the abdomen.”

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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