Print

A Abdominals The abdominal muscles are located on the front of the body between the ribs and the pelvis. These muscles support the trunk, assist with body posture, allow move- ment, and hold the body’s organs in place by regulating internal abdominal pres- sure. The abdominal muscles also help to protect the underlying vital organs in the abdominal cavity. The main abdominal muscles are the rectus abdominis, the external and internal obliques, and the transversus abdominis. The rectus abdominis is the large muscle in the front and center of the abdo- men. It is located between the ribs and the front of the pelvis, originating at the pubic bone and attaching at the fifth and seventh ribs and at the sternum. These muscles are responsible for the “six-pack” often described in very fit people. The main function of the rectus abdominis is to move the portion of the body between the rib cage and the pelvis and to control the tilt of the pelvis and the curvature of the lower spine. The external oblique muscles are a pair of broad muscles that attach at ribs five through twelve and the iliac crest and pubic bone. It is the largest muscle on the front and sides of the abdomen. Broad and flat, it may not always be visible under the skin because many people have fat deposits overlying the area. The main func- tion of the external obliques is to laterally flex and rotate the trunk, or to bend sideways. These muscles pull the chest down and compress the abdominal cavity. The external obliques “suck in the gut” and flex the trunk when performing sit- ups or crunches. These muscles also have a limited role in flexing and rotating the spine. Interestingly, contraction of one of the external oblique muscles results in the flexion of the trunk on the opposite side (e.g., the left external oblique rotates and flexes the trunk to the right). The internal oblique muscles are a pair of muscles located deep below the external obliques. The internal obliques attach at the tenth to twelfth ribs and the iliac crest and pubic bone. These muscles rotate and side bend the trunk by pulling the rib cage toward the hip and lower back. They support the abdominal wall and help maintain abdominal pressure. The internal obliques also assist with breathing by pulling down the chest cavity as the diaphragm contracts, which increases lung volume. The transversus abdominis is the deepest muscle layer of the abdominal wall and extends between the ribs and the hips, originating at the iliac crest and attach- ing at the pubic bone area. It functions to stabilize the trunk, support the abdomi- nal wall, and maintain internal abdominal pressure. The abdominal muscles can be strained from repetitive activity, overstretching, overuse, or a forceful blow. Though the abdominal muscles are often targeted