,i6 



HUMAN ANATOMY. 



(a) THE RECTUS MUSCLES. 

 I. Rectus abdominis. 2. Pyramidalis. 



I. Rectus Abdominis (Fig. 523). 



Attachments. — The rectus abdominis forms a flat but strong muscle which 

 traverses the entire length of the ventral abdominal wall immediately lateral to the 

 linea alba. It arises from the anterior surface of the xiphoid process of the sternum 

 and from the fartilages of the fifth, sixth, and seventh ribs, and is iyiserted by a strong 

 tendon into the crest and symphysis of the pubis. 



Fig. 52 



^■^6- 



Pectoralis major. 



Rectus, cut and turned 

 up 



Cut edge of anterior 

 sheath of rectus 



Posterior sheath of rectus 



External oblique 



Semilunar fold 



Transversalis fascia 

 Deep epigastric artery. 



Rectus, stump 

 Saphenous opening 



Tendon of rectus 



Sheath of rectus, turned over 



Tendinous intersection 



Rectus 



Crest of ilium 



Anterior superior iliac 



spine 



Pyramidalis 



External 

 abdominal ring 



Cribriform fascia 

 1 closing saphenous 



' opening 



Spermatic cord 



Muscles of anteii 



i' iininal wall. 



The fibres are directed longitudinally, and are interrupted along three and 

 occasionally four transverse lines by tendinous intersections of the muscle. One of 

 these inscriptiones tendinecE occurs about the level of the umbilicus, another, often 

 affecting only the medial portion of the muscle, corresponds approximately to the 

 lower margin of the thorax, and the third lies about midway between the two. The 

 fourth, when present, frequently is limited to the lateral portion of the muscle, and 

 occurs about midway between the level of the umbilicus. and the crest of the pubis. 



