388 MUSCLES. 



minae, terminating in the linea alba; one of which goes before 

 and the other behind the pyramidalis muscle, so that a sheath 

 is thus formed for it. 



Use; to compress the contents of the abdomen.* 



4. The Rectus Mdominis, 



Is seen beneath the tendons of the other muscles on either 

 side of the linea alba. Its origin is by a flat tendon of an inch 

 or more in breadth from the symphysis pubis and the upper 

 posterior part of the body of the pubes. The muscle increases 

 gradually in its ascent to the breadth of three or four inches. 

 The tendinous intersections, confining it to the tendinous sheath 

 in front, are fixed at the places mentioned as linese trans versa?; 

 hut, for the most part, they do not extend through the muscle. 

 When the origins of the Recti are examined from behind, it 

 will be seen that the internal edge of one tendon, just above the 

 symphysis pubis, overlaps the corresponding part of the other; 

 also, that a small pyramidal ligament finishes more completely 

 the structure just above the symphysis pubis; this ligament is 

 called by M. G. Breschet, the Superior Pubic. 



The Rectus is inserted fleshy into the base of the cartilago- 

 ensiformis, and into the cartilages of the fifth, sixth, and se- 

 venth ribs. 



It draws the thorax towards the abdomen.t 



5. The Pyramidalis, 



Is at the lower front part of the rectus, and is about three 

 inches long. It arises somewhat thick, tendinous, and fleshy, 

 from the upper part of the pubes, from near its spine to the sym- 

 physis, between the rectus behind and the insertion of the ex- 



* Varieties. Sometimes transverse tendinous fibres creep across its belly, and 

 on other occasions a small transverse muscle is present, which decussates the 

 larger, and is inserted into the twelfth rib. 



f Varieties. If there are eight sternal ribs, then this muscle has an additional 

 costal insertion. It sometimes sends a fasciculus to the fourth rib; and I have 

 seen it ascending over the pectoralis major, to the root of the neck, as occurs in 

 mamraiferous animals. 



