THE LARGE INTESTINE. 415 



runs slightly oblique to the fibres of the external oblique and almost exactly in 

 the direction of the fibres of the internal oblique and transversalis (Fig. 426). 



As soon as the peritoneum is opened the omentum may present itself. This is 

 to be displaced to the left. Some coils of small intestine if present are to be pushed 

 also to the left. The intestine then presenting will be the colon or caecum, because 



Fibres of the external oblique 



Fibres of the internal oblique 



Fibres of the transversalis 



Anterior part of sheath of the rectus 



Rectus muscle 



Posterior part of the sheath of the 



rectus 



The longitudinal operation passes through and 

 -n ^ x tne externa j oblique, 



it is fastened to the posterior wall and cannot be moved away. The longitudinal 

 bands will also identify it. Another way is to pass the finger down the inside of the 

 abdominal wall and the floor of the iliac fossa and bring up the caecum. Always 

 work from the outer toward the inner side, because (see Fig. 422) the ascending 



Ileum 



Rectus muscle drawn inward 



Sheath of rectus opened 

 Fibres of the internal oblique and 

 transversalis muscles 

 External oblique aponeurosis 



FIG. 426. Author's incision for appendicitis. The caecum has been lifted out of the wound, bringing with it the 



appendix. 



colon and caecum almost always lie against the abdominal wall on the surface of the 

 iliacus muscle above the outer half of Poupart's ligament. 



The caecum is to be drawn up and turned toward the head. The longitudinal 

 bands, all of which lead to the appendix, are to be followed down over the caecum 

 until the appendix is reached. If the bands are not visible, identify the ileocsecal 

 junction and about 2 cm. ( ^ in. ) or less below and behind it will be the root of the 



