THE ABDOMEN. 33 



67. Bony prominences. The anterior superior spine of 

 the ilium, the spine of the pubes, and the line of Poupart's 

 ligament, are landmarks with which every surgeon should be 

 thoroughly familiar. 



68. Spine of ilium. The spine of the ilium is the spot 

 from which we measure the length of the lower extremity. It is 

 a valuable landmark in determining the nature of injuries to 

 the pelvis and the hip. The thumb easily feels the spine, even 

 in fat persons. Its position with regard to the trochanter major 

 should be carefully examined. The best way to do this is 

 to place the thumbs firmly on the opposite spines, and to 

 grasp the trochanters with the fingers. Any abnormal posi- 

 tion on one side is thus easily ascertained with the sound 

 side as a guide. 



69. Spine of pubes. The spine of the pubes is the best 

 guide to the external abdominal ring. It cannot easily be 

 felt by placing the finger directly over it, since it is generally 

 covered by fat. To feel it distinctly, we should push up the 

 skin of the scrotum and get beneath the subcutaneous fat. 

 If there be any difficulty in finding it, abduct the thigh, and 

 the tense tendon of the adductor longus will lead up to it. 



The position of the spine of the pubes is appealed to as a 

 means of diagnosis in doubt between inguinal and femoral 

 hernia. The spine lies on the outer side of the neck of an 

 inguinal hernia, on the inner side of the neck of a femoral. 



The spine of the pubes is nearly on the same horizontal 

 line as the upper part of the trochanter major. In this line, 

 about one full inch external to the spine, is the femoral ring. 

 Here is the seat of stricture in a femoral hernia. 



70. Poupart's lig-ament, or crural arch. The line of 

 Poupart's ligament (crural arch) is in most persons indicated 

 by a slight crescent- like furrow along the skin. It corresponds 

 with a line drawn not straight, but with a gentle curve down- 

 wards from the spine of the ilium to the spine of the pubes. 

 With the help of the preceding landmarks it is easy to find 

 the exact position of the external and internal abdominal 

 rings, and the direction of the inguinal canal. 



71. Abdominal ring-s. The external abdominal ring is 



D 



