360 



MUSCLES AND FASCIA. 



of the ring, to the linea alba. They diverge as they ascend, and form a thin, 

 triangular, fibrous band, which is called the triangular ligament. 



In the aponeurosis of the External Oblique, immediately above the crest of 

 the os pubis, is a triangular opening, the external abdominal ring, formed by a 

 separation of the fibres of the aponeurosis in this situation : it serves for the 

 transmission of the spermatic cord in the male, and the round ligament in the 



Fig. 230. The External Oblique Muscle. 



female. This opening is directed obliquely upwards and outwards, and cor- 

 responds with the course of the fibres of the aponeurosis. It is bounded, below, 

 by the crest of the os pubis ; above, by some curved fibres, which pass across 

 the aponeurosis at the upper angle of the ring, so as to increase its strength ; 

 and, on either side, by the margins of the aponeurosis, which are called the 

 pillars of the ring. Of these, the external, which is, at the same time, inferior, 

 from the obliquity of its direction, is inserted into the spine of the os pubis. 

 The internal, or superior pillar is attached to the front of the symphysis pubis, 

 and interlaces with the corresponding fibres of the opposite muscle, the fibres 



