The abdominal muscles more commonly known as abs or six pack for short located on the front lower half of the human torso. Four core muscle groups make up the the Abdominal muscles as we know them and they are as follows;
- Rectus Abdominal
- Exernal Obliques
- Internal Obliques and
- Transverse Abdominals.
These muscles combine to provide different important functions for our bodies such as providing movement, postural support to the trunk, protecting the inner organs and assisting in the breathing process. The abdominal muscles work very closely with the muscles of the back to assist in these functions and they play a very important role in defining the form (posture) of our body.
1. Rectus Abdominal
The Rectus Abdominal is a long superficial muscle extending vertically on each side of the human abdomen from the lower rib cage down to the pubic bone. There are two parallel muscles separated into 4 smaller paired compartments by the Linea Alba, giving it the commonly referred to name of the six pack due mainly to the fact the lower two compartments are close to the pubic bone and therefore not visible. The origin point of attachment of the Rectus Abdominal Muscle is the Pubic Crest and the Pubic Symphysis. The insertion point of attachment of the Rectus Abdominis is the xiphoid process and the costal cartlages of the 5th to 7th ribs. The main function of the Rectus Abdominis Muscle is flexion of the trunk, in other words the bending of one’s spine/back forward. The lower muscle fibbers also contribute to the flexion of the hips or tilting the hips forward. In addition to these functions the Rectus Abdominis plays a large role in breathing as it is the muscle used when forcefully expelling air from you lungs and assist in keeping internal organs in place.
The External Oblique muscles are the largest and most superficial of all the abdominal muscles. The opposite to the internal Oblique muscle, they extend downwards and inwards and are the strongest of all the abdominal muscles. The origin points are the anterlateral boarders of the lower 8 ribs and the insertion points are the outer anterior half of the Iliac Crest, the Pubic Crest and Tubercle and the aponeurosis of the anterior rectus sheath. Working closely with the internal oblique muscles, the main function of the external oblique muscles are to abduct and rotate the trunk, support the abdominal wall, assist the lungs with forced expiration as well as aiding in raising the intra-abdominal pressure by flexion of the trunk (pulling the chest downwards).