34 LANDMARKS MEDICAL AND SURGICAL. 



situated immediately above the spine of the pubes. It is 

 an oval opening with the long axis directed obliquely 

 downwards and inwards. Though its size varies a little in 

 different persons, yet as a rule it will admit the end of the 

 little finger, so that we can tell by examination whether it be 

 free or otherwise. To ascertain this, the best way is to push 

 up the thin skin of the scrotum before the finger ; then, by 

 tracking the spermatic cord, the finger readily glides over 

 the crest of the pubes and feels the sharp margins of the ring. 

 The position of the internal ring is about midway between 

 the spine of the ilium and the symphysis of the pubes, and about 

 two-thirds of an inch above Poupart's ligament. 



72. Ing-uinal canal. The position of the external and 

 internal abdominal rings being ascertained, it is plain that the 

 direction of the inguinal canal must be obliquely downwards 

 and inwards, and that its length in a well formed adult male 

 is from one and a half to two inches, according as we include 

 the openings or not. In very young children the canal is much 

 shorter and less oblique, the inner ring being behind the outer. 

 With the growth of the pelvis in its transverse direction, the 

 anterior spines of the ilia become farther apart, and thus draw 

 the internal ring more and more away from (i.e. to the outer 

 side of) the external. 



73. Spermatic cord. The spermatic cord can be felt as 

 it emerges through the external ring, and its course can be 

 tracked into the scrotum. The vas deferens can be distinctly 

 felt at the back of the cord, and separated from its other 

 component parts. 



74. Epigastric artery. The direction of the deep 

 epigastric artery corresponds with a line drawn from the 

 inner border of the internal ring up the middle of the rectus 

 muscle, towards the chest. 



In thin persons the absorbent glands which lie along 

 Poupart's ligament can be distinctly felt. They are usually 

 oval, with their long axes parallel to the line of the ligament. 



75. Abdominal viscera. Now let us see how far we can 

 make out externally the position and size of the abdominal 

 viscera. 



