The function of the abdominal muscles are to protect the internal organs in the abdominal and pelvic regions and provide postural support. There is not one, but several muscles involved in the support of the abdominal area.
Rectus abdominus is the large abdominal muscle in the center of the abdominal region. It controls pelvic tilt. The internal and external obliques are the abdominal muscles located adjacent to the rectus abdominus. The internal oblique stretches from the front of the abdomen to the back of the torso and aids in performing certain body functions such as breathing. The external obliques assist in rotating motions.