THE ABDOMEN 641 



and each extends from the anterior superior iliac spine to the 

 umbilicus. 



The anterior superior spinous process of the ilium is situated 

 at the anterior extremity of the iliac crest, and, being very super- 

 ficial, it can be readily felt. It is on the same level with that of 

 the opposite side, and therefore a line connecting the two should 

 be quite horizontal. The plane of this interspinous line is rather 

 lower than the promontory of the sacrum. The anterior superior 

 iliac spine is the point from which the measurement of the lower 

 limb is taken, the other point being the internal malleolus. This 

 spine is also a good ready guide to the position of the great tro- 

 chanter, which is situated about 4 inches below it, and about 

 4^ inches behind a line let fall vertically from it. 



The pubic spine is situated at the lower and inner part of the 

 anterior abdominal wall about i\ inches outside the upper part of 

 the symphysis pubis. It is sometimes a sharp-pointed process, 

 and then it can readily be felt beneath the integument. In most 

 persons, however, it takes the form of a more or less indistinct 

 tubercle, and cannot readily be made out. In such cases the 

 scrotal integument may be invaginated with the finger, and so the 

 adipose tissue raised from over the spine. If it cannot be felt in 

 this way the thigh should be well abducted to render prominent 

 the adductor longus muscle, the tendon of origin of which will serve 

 as a guide to the spine, which lies above and to the outer side of it. 

 The pubic spine is the guide to the external abdominal ring, the 

 crural or femoral ring, and the saphenous opening. The external 

 abdominal ring is situated immediately above, and to the outer side 

 of, the pubic spine. In exploring the ring the best way to proceed 

 is to invaginate the scrotal integument, and carry the examining 

 finger up the inner side of the spermatic cord, when the ring will be 

 reached. In normal circumstances it should admit the point of 

 the little finger. In making this examination the spermatic cord 

 is readily felt, and the vas deferens can be distinguished as a firm 

 cord-like structure lying at its back part, and easily separable from 

 the other constituents of the cord. In the female the round liga- 

 ment of the uterus takes the place of the spermatic cord, but, 

 being a very ill-defined structure, it usually escapes detection. 

 The femoral ring is situated fully i inch external to the pubic 

 spine in a line drawn transversely outwards from that spine across 

 the front of the thigh. The saphenous opening is situated below, 

 and a little external to, the pubic spine. 



The pubic crest extends transversely inwards for about i\ inches 

 from the pubic spine, and it terminates in the pubic angle 

 which surmounts the internal surface of the pubic body, and is 

 usually a rudimentary tubercle. The crest may be felt with the 

 finger as the external abdominal ring, of which it forms the base, 

 is being explored. 



Poupart's ligament can be felt as a tense band, especially 

 when the thigh is extended, abducted, and rotated outwards, 



41 



