Chap, xvi.] THE ABDOMINAL PARIETES. 275 



experiences a violent respiratory movement in the 

 form of a deep gasp. When the abdominal muscles 

 are firmly fixed the lower ribs are also rigid, and 

 respiration is limited to the higher ribs and to the 

 thorax proper. 



There are other practical points about these nerves. 

 In caries of the spine, and in certain injuries to the 

 column, the spinal nerves may suffer injury as they 

 issue from the vertebral canal. This injury may show 

 itself by modified sensation in the parts supplied by 

 such nerves. Thus in Pott's disease the patient often 

 complains of a sense of tightness about the abdomen, 

 as if a cord were tied around it. This sense of 

 constriction depends upon an impaired sensation in the 

 parts supplied by a certain pair of nerves ; or, if the 

 sense of constriction be wider spread, by two or more 

 pairs of nerves. In other cases a sense of pain may 

 take the place of that of constriction. It would hardly 

 be believed that spinal disease has been mistaken for 

 " belly-ache." But many such cases have been recorded. 

 A child complains of pain over the pit of the stomach 

 or about the umbilicus, and this feature may quite 

 absorb for a while the surgeon's attention. The 

 abdomen is carefully poulticed, while the only mischief 

 is in the vertebral column, Other symptoms, however, 

 develop, and it becomes evident that the pain is 

 due to pressure upon the nerves supplying the skin 

 over the epigastric or umbilical regions, and that that 

 pressure is a circumstance in the course of spinal bone 

 disease. The site of the painful part depends, of 

 course, upon the position of the spinal ailment, and 

 thus the cutaneous symptoms may serve to localise 

 the caries in the vertebrae. Thus the skin over the 

 " pit of the stomach " is supplied by the sixth and 

 seventh dorsal nerves, the tenth nerve is nearly in a 

 line with the umbilicus, while the two lumbar nerves 

 run close above Pou part's ligament. The position of 



