THE ABDOMEN. 29 



the inferior angle slides forwards, and is well held under the 

 latissimus dorsi. 



60. For the medical examination of the back, the patient 

 should sit with the arms hanging between his thighs, to lower 

 the scapulae as much as possible. In this position the spine 

 of the scapula corresponds (nearly) with the fissure between 

 the upper and lower lobes of the lung ; the apex of the lower 

 lobe being about the level of the third rib. 



THE ABDOMEN. 



The student is assumed to be familiar with the conven- 

 tional lines dividing the abdomen into regions. 



61. Abdominal lines. The linea alba, or central line 

 of the abdomen, marks the union of the aponeuroses of the 

 abdominal muscles. It runs from the apex of the ensiform 

 cartilage to the symphysis pubis. As this line is the thinnest 

 and least vascular part of the abdominal wall, we make our 

 incision along it in ovariotomy, and in the high operation of 

 lithotomy ; in it, we tap the abdomen in ascites, and the dis- 

 tended bladder in retention of urine. 



The so-called ' linea semilunaris,' at the outer border of 

 the sheath of the rectus, corresponds with a line, drawn slightly 

 curved (with the concavity towards the linea alba), from the 

 lowest part of the seventh rib to the spine of the pubes. This 

 line would be in an adult about three inches from the umbi- 

 licus ; but in an abdomen distended by dropsy or other cause, 

 the distance is increased in proportion. 



It is important to know the position of the ' lineae trans- 

 versae,' or tendinous intersections across the rectus abdominis. 

 There are rarely any below the umbilicus, and generally three 

 above it. The first is about the level of the umbilicus. The 

 second is about four inches higher that is, about the level of 

 the lowest part of the tenth rib. These are the principal 

 lines, and they divide the upper part of each rectus into two 

 nearly quadrilateral portions, an upper and a lower : of these, 

 those on the right side are a trifle larger than on the left. We 



