336 SURGICAL APPLIED ANATOMY. [Chap.xvn. 



found in this position belong to the terminal part of 

 the ileum, and to that part of the intestine that has 

 been already alluded to as possessing the longest 

 mesentery (page 325). The ileum is the part of the 

 intestine that is most frequently found in inguinal 

 and femoral hernise. It is also the part most usually 

 involved in cases of strangulation by internal bands, 

 by holes in the mesentery, etc. 



Of all the viscera the small intestines are the most 

 exposed to injury, and at the same time it must be 

 noted that by their elasticity, and by the ease with 

 which their coils slide over one another and so elude 

 the effects of pressure, they are the best adapted to 

 meet such injuries as contusions and the like. A 

 minute punctured wound of the small gut does not 

 lead to extravasation of contents. The muscular coat 

 contracts and closes the little opening. Thus, in ex- 

 cessive tympanitis the bowels are often freely punc- 

 tured in many places with a fine capillary trochar, to 

 allow the gas to escape, without any evil resulting. A 

 case of intestinal obstruction of sixteen weeks' dura- 

 tion is reported, in which the abdomen was punctured 

 150 times (Boston Med. Journ.). If the wound be a 

 little larger the loose mucous membrane becomes 

 everted or protruded through the wound and effec- 

 tually plugs it. Gross found that a longitudinal cut 

 in the small bowel two and a half lines in length was 

 immediately reduced to a wound one and three- 

 quarter lines in length by muscular contraction, and 

 that the eversion of the mucous membrane in addition 

 to this contraction entirely sealed the opening. 



Owing to the greater power of the circular layer 

 of muscle a longitudinal wound gapes more than a 

 transverse wound, and, in consequence of the greater 

 muscular development of the jejunum, wounds of that 

 part gape more than do those of the ileum. Trans- 

 verse wounds gape most when inflicted across the free 



