This is the Rectus Abdominis
AKA “Abdominal Muscles” and “Abs”
- the superior edge of the pubis bone
- the pubic symphysis in the pelvis.
- The inferior edges of the costal cartilages of the fifth through seventh ribs
- The xiphoid process of the sternum.
- performs the important task of flexing the torso and spine in the abdominal region.
- It does this by pulling the rib cage closer to the pelvis.
- The rectus abdominis can also tense to contract the abdomen without moving the torso, as in sucking in one’s gut.
- Assists in breathing.
- when forcefully exhaling, as seen after exercise as well as in conditions where exhalation is difficult such as emphysema.
- It also helps in keeping the internal organs intact and in creating intra-abdominal pressure, such as when exercising or lifting heavy weights, during forceful defecation (bowel movements) or childbirth.
What Gives the “Abs” Their Shape?
- Bands of connective tissue called the Tendinous Intersections traverse the Rectus Abdominis, which separates this parallel muscle into distinct muscle bellies.
- Between the rectus abdominis muscles is a thick mass of white fibrous connective tissue called the Linea Alba that unites the abdominal muscles of the left and right sides.
- The outer, most lateral line, defining the “abs” is the Linea Semilunaris (attachment sites for the external oblique and the transverse abdominis).