Abdominals

3.Internal Obliques

The internal Oblique muscles is found lying in-between the external Oblique and Transversus abdominis. The origin attachment point of the the internal oblique muscle is the anterior two thirds of the iliac crest, the lateral two thirds of the inguinal ligament and the lumbar fascia.  The insertion attachment points are the costal cartilages of ribs 8 to 12 and the aponeurosis of the rectus sheath and a conjoint tendon to the Pubic crest. Working closely with the external oblique muscles the internal oblique muscles function to abduct and rotate the trunk, to abduct and rotate the trunk, supporting the posterior wall of the inguinal  canal, assist the lungs with forced expiration as well as aiding in raising the intra-abdominal pressure.

The Traverse Abdominals are the deepest muscles of the Abdominal muscle group.

4.Transversus Abdominis

The Transverse Abdominis is a flat triangular muscle the deepest of the abdominal muscles, and as the name suggests it transverses horizontally from the front to the back of the abdomen. Unlike the other muscles of the abdomen, the Transversus Abdominis function is not primarily for postural support but rather an important muscle to aid in our breathing especially forced exhalation, compressing the ribs and viscera assisting in providing thoracic and pelvic stability and during pregnancy assisting women in the delivery of their baby.

The Transversus Abdominis lies underneath the inner oblique and has multiple origin and insertion attachment points with the origin points being the Costal Margin, lumbar fascia, anterior two thirds of iliac crest and lateral half of inguinal ligament. The Insertion attachment points are Aponeurosis of posterior and anterior rectus sheath and conjoint tendon to pubic crest and pectineal line.

A great example of the abdominal muscles