The CROSS MUSCLE OF THE ABDOMEN originates with 6 digits from the inner face of the last six costal cartilages. It also originates posteriorly from the deep leaflet of the thoracolumbar or lumbodrosal fascia, from the inner lip of the iliac crest, from the anterior superior iliac spine and from the lateral half of the inguinal ligament (anterior). Its fibers, which have a transverse course, are placed deeply in the internal oblique muscle.
It is inserted with its aponeurosis in the upper part of the linea alba; on the inner face of the costal cartilage of the last 6 ribs (7a-12a).
By contracting, it carries the ribs medially (expiratory muscle). It has a role in maintaining posture. Its contraction also determines an increase in abdominal pressure, necessary to withstand the forces acting on the spine during certain exercises.
It is very important for the aesthetics of the person because it forms a real muscular corset able to contain the belly. Being a purely expiratory muscle, it trains exhaling deeply during the contraction of the abdominal muscles.
It is innervated by the intercostal nerves (T7-T12), ileoipogastric and ileoinguinal nerves of the lumbar plexus (L1)
| ORIGIN With 6 digits from the inner face of the last 6 costal cartilages (7a-12a); from the deep leaf of the thoracolumbar fascia; from the internal branch of the iliac crest; from the anterior superior iliac spine; from the inguinal ligament (lateral half) |  |
| INSERTION With an aponeurosis in the upper part of the linea alba to which the aponeuroses of the transversus and of the internal oblique join; on the joint tendons (ant.) and on spinous processes of L1-L5 | |
| ACTION It carries the ribs medially (expiratory muscle); increases abdominal pressure | |
| INNERVATION Nerve i ncostcostali (T7-T12), ileoipogastric and ileoinguinal nerves of the lumbar plexus (L1) |
| Upper limb | Lower limb | Trunk | Abdomen | Articles |
