THE MUSCULAR SYSTEM 6? 



lage, and below with the pubis. ' v That portion of the 

 aponeurosis of the external oblique which extends from 

 the anterior superior spine of the ilium to the spine of 

 the pubis is known as Poupart's ligament.) Gimbernat's 

 ligament is an extension of the latter to the iliopectineal 

 line. Action, compresses the viscera, flexes the thorax on 

 the pelvis or the pelvis on the thorax, according to which 

 is the fixed point, and also assists expiration. Nerve- 

 supply, the lower intercostals. 



The internal oblique arises from Poupart's ligament, v 

 from the middle lip of the crest of the ilium, and from the 

 lumbar fascia. Insertion, crest of os pubis with the trans- 

 versalis muscle forming the conjoined tendon, which 

 strengthens the external abdominal ring; it also blends 

 with the external oblique to form the linea alba, and with 

 the transversalis muscles. Action, same as that of the 

 external oblique. Nerve-supply, lower intercostals, ilio- 

 hypogastric, and ilio-inguinal. 



The muscles just described are broad and cover the 

 greater part of the abdominal wall; they are, therefore, 

 to be considered in operations in this locality. 



The muscles of the abdomen that have not been de- 

 scribed may be studied from the illustrations. The 

 student should observe especially the linea alba, a tendi'j 

 nous raphe or cord seen as a dark, perpendicular streak irj 

 the middle of the abdomen. This is of some importance, 

 and is of interest to the nurse, especially in regard to the 

 discoloration that takes place in pregnant women. 



Gray says: The abdominal muscles have a threefold 

 action: They compress the abdominal wall during the 

 process of defecation; they assist in the act of respiration, 

 and they help in the expulsion of the fetus; the urine is 

 expelled through the agency of this combination of mus- 

 cular force, and by it, through upward pressure, the stom- 

 ach is relieved of its contents. From this it will be seen 



