THE ABDOMEN 639 



the vagina terminate in the internal iliac glands, and the deep 

 h-mphatics of the corpora cavernosa clitoridis, having accompanied 

 the dorsal vein of the cHtoris, also terminate in the internal iliac 

 glands. 



The pudic nerve and its branches are similar to those in the male, 

 the superficial perineal nerves being distributed to the labia majora. 



ABDOMINAL WALL. 



Landmarks. — ^The position of the linea alba is indicated by the 

 mid-abdominal groove, which extends from the ensiform process 

 of the sternum to the umbilicus, and the mid-abdominal line, which 

 extends from the umbilicus to the upper part of the s^Tnphysis 

 pubis. After removal of the integument the linea alba presents 

 a dense white appearance, and is slightly depressed below the level 

 of the adjacent surfaces. It is produced by the decussation of the 

 aponeuroses of the abdominal muscles of opposite sides, except the 

 recti, and it is divided into two parts, supra-umbilical and infra- 

 umbilical. The supra-umbilical part is about ^ inch broad, the 

 recti being here separated to that extent. The infra- umbilical part 

 is only about ^ inch wide on account of the approximation of the 

 recti in this situation. Over the whole extent of its posterior or 

 abdominal surface it is invested by the parietal peritoneum, unless 

 in cases of abnormal distension of the bladder, when the peritoneum 

 is stripped from the lower part to an extent corresponding with 

 the height to which the distended bladder ascends. The anterior 

 abdominal wall is thinner and less vascular along the linea alba 

 than at any other part. This line is therefore selected for such 

 operations as suprapubic lithotomy, tapping a distended bladder 

 above the symphysis pubis, and ovariotomy. 



The structures which axe divided in opening the abdominal cavity along 

 the linea alba are as follows : the integument, the decussating fibres of 

 the aponeuroses of opposite sides, fascia transversalis, subperitoneal areolar 

 tissue, and parietal peritoneum. There are no bloodvessels of any importance 

 in this situation. 



The posterior aspect of the linea alba has important visceral 

 relations. The left lobe of the liver lies behind it for about 2 inches 

 below the ensiform process of the sternum. The relation of the 

 stomach to it is variable. When the viscus is moderately distended 

 it lies behind the linea alba below the margin of the liver. In the 

 empty condition, however, it recedes from the linea alba, and this 

 gives rise superficially to the epigastric depression, or scrohiculus 

 cordis (' small trench of the heart '). The transverse colon, covered 

 by the great omentum, as it crosses from right to left, usually lies 

 behind the linea alba just above the imibilicus. The coUs of the 

 jejunum and ileum, also covered by the great omentimi, lie behind 

 it below the umbilicus. 



