168 ANATOMY OF THE ABDOMEN, ETC. 



also be traced in the fibres of the muscle to an anastomosis 

 with the terminal branches of the internal mammary artery. 

 It was by the aid of these anastomoses that some of the 

 old anatomists endeavored to explain the intimate relation- 

 ship between the genital organs and the mammary gland. 

 At the lower part of the inner surface of the rectus muscle 

 will be seen a thin layer of diverging fibres, springing from 

 the insertion of Poupart's ligament into the pectineal line, 

 and ascending upward and inward to the linea alba in which 

 they are lost; it is called the triangular ligament. 



ANATOMY OF INGUINAL HERNIA. 



It is always desirable, if possible, to make a special dissection of 

 the inguinal region ; but if the student has left the lower part of the 

 abdominal muscles as directed, it may be very satisfactorily examined 

 after the general dissection is accomplished. The dissection can be 

 advantageously performed only upon the male subject. 



Under the influence of violent exertions, and sometimes 

 passive!}', a portion of the contents of the abdomen may 

 be protruded at such parts of its walls, as, from their con- 

 formation, are weaker or less protected than others. This 

 protrusion is called hernia, or rupture. The inguinal region 

 is a point at which it frequently occurs. To understand 

 why this region is liable to this accident, it is necessary to 

 examine it specially in this relation. 



The INGUINAL REGION is included between Poupart's liga- 

 ment, the linea alba, and an imaginary transverse line from 

 the latter to the anterior superior spinous process of the 

 ilium ; most of its parts have already been separately 

 described. The perforation of the external oblique by the 

 spermatic cord, the thinness, or partial deficiency of the 

 fibres of the internal oblique and trans versalis muscles, 

 make it apparent that less resistance would be offered here 

 than elsewhere to the superincumbent weight of the abdo- 

 minal viscera, and that their impulsion against it, during 

 efforts which contracted the diaphragm and abdominnl 

 muscles, would render protrusion of the intestines or 

 omentum at this point a very conceivable occurrence. 



The superficial fascia, but for its relation to the anatomy 

 of hernia, would be considered merely as the sheath of the 

 external oblique, in which a certain amount of fat was 

 deposited. It is usually spoken of as consisting of two 

 layers, separated by the superficial epigastric artery and 

 vein. Unless a special dissection of it has been made, it 



