1018 THE ORGANS OF DIGESTION. 



Internally : 



Head and neck of pancreas ; 

 Aorta ; 



Fourth, third, and second lumbar vertebrae ; 

 (Third, second, and first in child). 



Terminal, or Fifth Portion. 



Superiorly : 



Body of pancreas. 



Anteriorly : 



Duodeno-jejunal angle ; 

 Left layer of mesentery. 



Externally : 



Inner margin of left kidney. 



Means of Fixation. Neither peritoneal adhesions nor peritoneal ligaments 

 really fix an organ ; if the latter ever does, it is because it contains vessels and 

 nerves and cellular tissue between its layers. 



The means here are 1. Biliary and pancreatic ducts. 2. Arteries which are 

 the conductors and support of fibro-nervous tissue. 3. Suspensory muscle of 

 Treitz supporting the duodeno-jejunal angle. 4. A cellular fold under the pan- 

 creas. (Treitz.) 



1. The ducts of the two glands, common bile-duct and the pancreatic, con- 

 tribute to the fixation of the duodenum, yet the lig. hepato-duodenale must 

 render service in resisting a downward pull, whereby the ducts would be stretched 

 and their functions disturbed. 



2. Two abdominal arteries are important in fixing the duodenum to the poste- 

 rior Avail: the coeliac axis above it and superior mesenteric above and in front, 

 which have retained their original positions of foetal life. There is a complete 

 anastomosis or arterial circle between these vessels, connecting the posterior 

 abdominal wall to the liver, stomach, pancreas, duodenum, and spleen. 



3. Fibro-nervous investments accompany the arterial circle formed of cellular 

 tissue and sympathetic nerve-plexuses. They have two roles : first, innervation 

 of the vessels, and secondly, support. The coeliac and solar plexuses support as 

 one the duodenum and its neighboring organs the liver, stomach, and pancreas. 



4. Muscle of Treitz. 



In 1853 Treitz described a muscle running from the duodeno-jejunal angle to 

 the diaphragm. Many have since described it for him. If the beginning of the 

 jejunum be pressed down, after turning up the stomach and transverse colon, a 

 ridge of peritoneum will be seen to extend from the duodeno-jejunal angle up 

 under the pancreas to the left crus of the diaphragm. This ridge is called the 

 ligament of Treitz. The original article l reads in substance thus 



"Raise the pancreas and detach it from the diaphragm. The duodeno-jejunal angle is 

 seen attached to the posterior abdominal wall by a muscle (Fig. 637). This muscle is small and 

 triangular and rises by its base from the superior border of the duodeno-jejunal curve and from 

 a part of the ascending duodenum. It passes toward the aortic orifice of the diaphragm and 

 near its centre continues into a tendon which becomes more narrow and loses itself in the ten- 

 dinous tissue surrounding the superior mesenteric artery and coeliac trunk, enveloping the 

 ganglia and nerves of the coeliac plexus. By traction these fibrous bands can be seen connected 

 with the inner pillars of the diaphragm, and commonly with the right border of the oesophageal 

 orifice. All subjects possess it; it is best developed in muscular individuals and with a low- 

 placed duodenum. Its tendon is 1.5 mm. long; the muscle 1 mm. thick. As to its function, 

 it does not^merit the name Levator duodeni ; its action is of little importance as a muscle; it 

 plays the r61e of a suspensory ligament and ought to be called Muscidus suspensnn'it* <lu,i<l, ni." 



The muscle is continuous with the longitudinal muscular layer of the duode- 

 num and is stronger the older the subject. 



1 Prager Vierteljahrcsschrifl, 1853, s. 113. 



