958 



THE ORGANS OF DIGESTION 



The great omentum. — It will be seen that the great onientuni is fonued of 

 four layers of peritoneum, though this is quite impossible to demonstrate in an 

 adult, the individual layers having become adherent. 



The great omentuni^ acts as a sort of apron, protecting the intestines and ])ro- 

 viding them with a heat-economising covering of fat. It is nearh' quadrilateral in 

 sha])e, and is variable in extent. 



In tig. 5(34 the great omentum is shown to be connected with the greater curva- 

 ture (^f the stomach on the one hand, and the transverse colon on the other. This 

 is the arrangement described in the text. Under certain conditions (as show^n in 

 fig. 5G3) the posterior layer of the great omentum returns to the posterior parietes, 

 and is independent of the transverse meso-colon. This variation is explained in 

 the account of the evolution of the peritoneum (page 1002). 



Mr. Lockwood has made some investigations on the lengths of the transverse 

 meso-colon and great omentum in thirty-three cases. In twenty, under the age of 

 forty-five, only one subject had a great omentum long enough to l:)e drawn beyond 

 the "pubic spine; in five, the omentum reached as far as the pubes. In the cases 

 beyond forty-five years, it Avas the exception rather than the rule to find an omen- 

 tum which could not l)e |)ulled l^eyond the lower limits of the abdomen. 



The lesser or gastro-hepatic omentum consists of a double layer of perito- 

 neum extending between the lesser curvature of the stomach and the transverse 



Fig. 564.- 



-DlAGRAM TO SHOW THE PERITONEUM AS SEEN IN VERTICAL SECTION. 

 (Allen Thomson.) 



GASTRO-HEPATIC OMENTUM 



MESO-COLON 

 TRANSVERSE COLON 



FORAMEN OF WINSLOW 



SMALL INTESTINE 



fissure of the liver. If the two anterior layers of the great omentum are traced 

 upwards, they are seen to enclose the stomach, and then join together again at the 

 lesser curvature to form the lesser or gastro-hepatic omentum (fig. 563). It is 

 connected al)ove with the transverse fissure of the liver, below with the upper curva- 

 ture of the stomach; the left extremity encloses the oesophagus; the right border 

 contains the hepatic vessels, and is free, forming the anterior boundary of the 

 foramen of Winslow. 



The gastro-splenic omentum connects the left extremity of the stomach with 

 the S])leen, continuing the layers of peritoneum which enclose the stomach. 



The gastro-phrenic and phreno-colic ligaments. — As the peritoneum passes 

 from the diaphragm to the stomach it forms a small fold just to the left of the 

 oesophagus. This is the gastro-phrenic ligament. A stout fold of the membrane 

 also extends from the diaphragm (opposite the tenth and eleventh ribs) to the 

 spleniit fiexurc of the colon, and is known as the phreno-colic or costo-colic ligament. 



Subperitoneal connective tissue. — An elaborate account of this tissue has 

 been written by Mr. Anderson and INIr. Makins. According to these observers, 

 ' the su1)])(n-itoneal and subpleural fascite are to be regarded as a portion of a wide 

 system of mesoblastic connective tissue which surrounds the great vessels of the 

 trunk, accompanying these branches from origin to termination, and extending 

 mainly in the form of perivascular sheaths to all })arts of the body.' 



