The rectus abdominis is a fairly slender muscle that runs vertically across the front of the abdominal wall. The right and left halves are separated by a tendinous strip about an inch wide called the linea alba. The muscle fibers run parallel to one another and are crossed by three tendons, which provide the divisions usually seen in a person with little fat in the abdominal area and a well-developed rectus abdominis muscle, commonly known as being "ripped". The rectus abdominis follows a curved line when at rest, and when contracted it becomes straight.
Origin
The rectus abdominis originates on the crest of the pubis.
Insertion
It inserts on the cartilage of the fifth, sixth, and seventh ribs.
Function
Flexes the spinal column and draws the sternum toward the pelvis.
