342 ABDOMEN 



inferior part is subdivided into horizontal and ascending 

 sections. The greater portion of the superior part is 

 surrounded by peritoneum which is continuous below with 

 the greater omentum, and above with the lesser omentum. 

 but its terminal portion is devoid of peritoneum behind and 

 below. The descending part is covered by the peritoneum in 

 front, and on the right side, except where it is crossed by the 

 transverse colon. The horizontal portion of the inferior part 

 is covered in front and below ; and the ascending portion of 

 the inferior part is covered in front and on the left side. 

 The remaining surfaces of the descending and inferior parts 

 of the duodenum are devoid of peritoneum, and they lie in 

 relation either with other viscera, or with large blood-vessels, 

 or with the posterior wall of the abdomen. 



Pars Superior, The superior part of the duodenum is two 

 inches in length ; it lies in the epigastric region, and for about 

 an inch or more from the pylorus it is enveloped by the 

 same two layers of peritoneum which invest the stomach ; 

 consequently, it enjoys a limited degree of movement. Its 

 terminal portion is covered with the peritoneum only on 

 its anterior and superior surfaces. Its position and rela- 

 tions are dependent upon the degree of distension of the 

 stomach. 



When the stomach is empty, and the pylorus is immediately 

 to the right of the median plane below the left lobe of the 

 liver, the superior part of the duodenum passes backwards 

 and to the right and slightly upwards, along the inferior surface 

 of the liver, to the neck of the gall-bladder. Its upper 

 surface is in contact at first with the under surface of the 

 left lobe of the liver, then it crosses the line of the umbilical 

 fissure of the liver, and in the latter part of its course it is 

 in relation with the lower surface of the quadrate lobe of the 

 liver. When the stomach is distended the pylorus moves 

 slightly to the right to the under surface of the quadrate lobe. 

 Then the superior part of the duodenum is slightly shortened 

 and it runs upwards and backwards beneath the quadrate 

 lobe, and its terminal extremity is lodged in a depression at 

 the left end of the porta hepatis. In both cases its termina- 

 tion bends suddenly downwards into the descending part. 

 The relations of the superior part of the duodenum are as 

 follows : above and in front, the visceral surface of the liver ; 

 below, the pancreas ; behind, the vena cava, the bile-duct, the 



