Rectus Abdominis is the most superficial of the abdominal muscles. It is this muscle which forms the six-pack shape!
Origin : Crest of the pubis.
Insertion : Xiphoid process (base of the sternum).
5th,6th and 7th costal cartilages.
Actions : Flexes lumbar spine.
Innervation : Ventral rami of thoracic nerves.
Daily uses : Moving from lying to sitting.
Example strengthening exercises : Crunches or sit-ups.
Example stretches : Abdominal stretch.