500 ABDOMEN 



relation, anteriorly, with the head of the pancreas and, 

 posteriorly, with the aorta. Behind it lies the anterior border 

 of the right psoas magnus muscle, with the right sympathetic 

 cord, and the left renal vein crosses behind it, unless the latter 

 vessel lies at a somewhat relatively higher level behind the 

 lower surface of the pancreas. 



Dissection. Cut through the peritoneum along the lines of its reflection 

 from the duodenum to the right kidney on the right, and from the duo- 

 denum to the posterior wall of the abdomen below and to the left, then turn 

 the second part medially, and the third and fourth parts upwards to examine 

 the posterior relations noted above. The first part of the duodenum and the 

 attached portion of the pyloric end of the stomach can be turned to the 

 right for the examination of the posterior relations of the first part of the 

 duodenum. 



Suspensory Muscle of the Duodenum and the Root of the 



Mesentery. The duodeno-jejunal flexure and the root of the 

 mesentery are held in position and prevented from slipping 

 downwards on the posterior wall of the abdomen by a band of 

 involuntary muscular fibres, which fixes them to the dia- 

 phragm. This band is called the suspensory muscle of 

 Treitz. It is attached above to the diaphragm, on the right 

 side of the cesophageal aperture. From this it proceeds 

 downwards, on the left side of the cceliac artery, to the 

 duodeno-jejunal flexure, into which a large number of its 

 fibres are inserted. The remaining fibres enter the mesentery 

 and find attachment to the peritoneum. In the child the 

 suspensory muscle is well marked and easily isolated, but 

 in the adult it loses its distinctly muscular character and 

 becomes more or less blended with neighbouring tissues. 



Pancreas. The pancreas is an elongated gland which 

 stretches transversely across the posterior wall of the abdomen 

 behind the stomach. For the most part it is situated in the 

 epigastric region, a small portion only of its left extremity 

 being placed in the left hypochondriac region. As in the case 

 of the other solid organs contained within the abdominal 

 cavity, its form is greatly modified by the condition of the 

 hollow viscera in its immediate vicinity, and its true shape 

 can only be ascertained by fixing it in situ by injections of 

 some hardening reagent. It may be described as consisting 

 of a head, a neck, a body, and a tail. 



The head of the pancreas is the flattened portion of the 

 gland which lies in front of the spine and occupies the con- 

 cavity of the duodenum. It rests upon the inferior vena cava 



