Rectum of the abdomen

The RIGHT MUSCLE OF THE ABDOMEN is one of the muscles that form the anterior abdominal wall. It originates with three digits from the outer face of the 5th and 7th costal cartilage and from the xiphoid process of the sternum.

The muscle fibers follow a descending course and are inserted with a short and robust tendon at the upper edge of the pubis, between the tubercle and the pubic symphysis.

The muscular belly generally has three to four transverse tendon inscriptions (clearly visible in lean subjects) and is divided from the contralateral rectum by the linea alba. It is also covered by the sheath of the rectus muscles, formed by the aponeuroses of the three lateral abdominal muscles (external and internal oblique, transverse abdomen).

With their action they lower the ribs (expiratory muscles), flex the chest on the pelvis or vice versa and increase the abdominal pressure. They participate in maintaining the physiological balance of the pelvis, reducing lumbar lordosis with their contraction. They therefore favor the retroversion of the pelvis (See: Importance of the abdominal muscles in the prevention of low back pain).

It is innervated by the n intercostal nerves (T5 -T12) and by the ileoipogstric nerve of the lumbar plexus (L1).

ORIGIN

With 3 fleshy bundles; the lateral and intermediate one originates from the inferior margin of the 5th and 6th costal cartilage, the medial one from the external face of the 7th costal cartilage and from the xiphoid process of the sternum;