426 ABDOMEN 



enlarged form of which it in reality is, and pass medially in front of the 

 ring, and then descend along its medial margin. In this case, the ring 

 is surrounded on all sides, except posteriorly, by important vessels. 



(2) It may pass downwards and backwards across the femoral ring. 



(3) It may run downwards between the ring and the external iliac vein 

 (vide p. 185). 



Medial to the femoral sheath the passage of a hernial protrusion behind 

 the inguinal ligament is effectually prevented by the lacunar ligament. 



Femoral hernia is more common in females, and inguinal hernia in 

 males ; and for the very evident reason that, in the female, the crural 

 canal is relatively larger, whilst in the male the passage of the spermatic 

 cord weakens the inguinal region more than the passage of the small 

 round ligament of the uterus in the female. 



Umbilical Hernia. If the dissector examines the umbilicus he will find 

 that he is dealing with a dense fibrous ring which embraces and fuses with 

 the remains of the umbilical vein, the remains of the obliterated parts 

 of the umbilical arteries and the urachus, the whole forming a dense 

 nodule of fibrous tissue closely connected with the superjacent skin. The 

 umbilicus marks the position where, during a large part of intra-uterine 

 life, the peritoneal cavity was prolonged through the abdominal wall into 

 the root of the umbilical cord which attached the foetus to the mother. 

 For a considerable time a portion of the gut lies in the extra- abdominal 

 sac in the root of the umbilical cord, but, before birth, it is withdrawn into 

 the abdomen and the sac shrinks and disappears. If a remnant of the sac 

 persists in the substance of the abdominal wall, after birth, the wall is 

 weakened and a portion of the abdominal contents may be forced into 

 the diverticulum, causing its distension and producing an umbilical hernia. 

 The anatomical coverings from within outwards would be (i) peritoneum, 

 (2) aponeurosis of the abdominal wall equivalent to the stretched linea 

 alba, (3) superficial fascia, (4) skin. 



If the foetal condition persists until birth a portion of the gut lies in the 

 umbilical cord, separating the three vessels ; and more than one case has 

 occurred in which the bowel has been cut when the cord was divided after 

 the birth of the child. 



ABDOMINAL CAVITY. 



When he has completed his examination of the regions 

 where hernia most commonly occurs the dissector should 

 proceed to study the abdominal cavity and its contents. 

 The abdomen must be more completely opened by an 

 incision carried upwards, from the umbilicus to the xiphoid 

 process, immediately to the left side of the median plane. 

 On throwing the two flaps thus formed upwards and laterally, 

 over the lower margin of the thorax, a strong fibrous cord, 

 the ligamentum teres, will be seen extending from the 

 umbilicus to the under surface of the liver. It is the 

 remains of the left umbilical vein of the foetus. As it 

 ascends, towards the liver, it gradually recedes from the 



