THE ABDOMINAL WALL. 



the thorax and the upper limit of the abdominal cavity; the diaphragm consequently corre- 

 sponds with the lower limit of the thoracic cavity. The abdominal cavity also extends down- 

 ward below the external boundary, formed by the iliac crests, and, although there is really no 

 sharp demarcation between the abdomen and pelvis, we designate the linea terminalis (pelvic 

 brim), the dividing-line between the true and false pelvis, as the inferior boundary of the abdom- 

 inal cavity. 



Inspection and Palpation. Inspection and palpation reveal a number of superficial 

 landmarks. The anterior median furrow of the thorax, passing into the scrobiculus cordis 

 (see page 91), is continued downward in the direction of the linea alba, and in spare muscular 

 individuals may be traced to the navel or even to the mons Veneris over the symphysis. To either 

 side of this median furrow may be observed the prominences caused by the recti muscles, the 

 external margins of which may be located by the presence of more or less distinct shallow grooves. 

 [The linea semilunares are represented by slightly curved lines from the tip of the ninth costal carti- 

 lages to the pubic spines. ED.] The furrows running transversely across the prominences of 

 the recti muscles correspond to their tendinous intersections; the portions of muscle situated be- 

 tween these tendinous intersections are occasionally so prominent that they may simulate tumors 

 (lipomata). [Occasionally, particularly when there is tenderness beneath, they simulate intra- 

 abdominal tumors. ED.] None of these landmarks are visible in the female, on account of the 

 abundance of subcutaneous fat ; during pregnancy the anterior median line of the abdomen is ren- 

 dered visible by the formation of pigment in the skin over the linea alba. With the subject in 

 the dorsal position, the vertebral column and the pulsations of the abdominal aorta may be pal- 

 pated if the abdominal walls are relaxed and not too thick. 



Upon the dorsal surface the posterior median furrow is continued downward over the spin- 

 ous processes to the sacrum and terminates in the shallow fossa which is designated as the sacral 

 triangle. The posterior surface of the sacrum may be felt in this region and, lower down, the 

 slightly movable coccyx. The palpating finger may be passed along the iliac crest to the anterior 

 superior spine of the ilium, and from here along the groin, upon Poupart's ligament, to the hori- 

 zontal ramus of the pubis and the pubic symphysis. [The posterior superior spinous processes 

 of the ilium are palpable, usually indicated by a depression, and are on the level of the spinous 

 process of the second sacral vertebra. ED.] 



The following lines are employed to divide the external surface of the abdomen into regions: 

 A horizontal line is drawn about the chest at the level of the root of the xiphoid process and serves 

 as a dividing-line between the chest and abdomen. A second line is drawn anteriorly connecting 

 the two lowest points of the costal margin and running posteriorly along the lower border of the 

 ribs to the twelfth dorsal vertebra. The epigastric region is situated between these two lines. 

 The central portion of the epigastric region, bounded laterally by the costal margins, is known 

 as the epigastrium; the remainder of this region forms the two hypochondriac regions, which 

 contain those abdominal organs which are situated beneath the costal margins. Below the epi- 

 gastric region is the mesogastric region, which extends downward, anteriorly to a line connecting 

 the two anterior superior spines, laterally and posteriorly to the iliac crests. The space 

 bounded by the line connecting the anterior superior spines of the ilium, by the groins, and by 

 the symphysis is known as the hypogastric region. Lines drawn downward from the lowest 



