THE LARGE INTESTINE 



1185 



empty condition it presents the appearance of an antero-posterior longitudinal 

 slit. Behind it is a mass of muscular and fibrous tissue, the anococcygeal body 

 (Symington) ; in front of it, in the male, but separated by connective tissue from 

 it, are the membranous portion and bulb of the urethra, and the fascia of the 

 urogenital diaphragm; and in the female it is separated from the lower end of 

 the vagina by a mass of muscular and fibrous tissue, named the perineal body. 



MUCOUS 

 MEMBRANE 



DILATATION 



OF VEINS 



COLUMNS OF. 



MORGAGNI 



VALVE OF 



MORGAGNI 



H I LTO N S 

 WHITE LINE 



MUSCULAR WALL 

 OF RECTUM 



INTERNAL HEMOR- 

 RHOIDAL PLEXUS 



DILATATION 

 OF VEIN 



COMMUNICATION BE- 

 TWEEN INTERNALAND 

 EXTERNAL HEMOR- 

 RHOIDAL PLEXUS 

 INTERNAL 

 SPHINCTER 



EXTERNAL 

 SPHINCTER 



LONGITUDINAL 

 TENDINOUS FIBRES 



SUBCUTANEOUS 

 CELLULAR TISSUE 



FIG. 1081. Inner wall of the lower end of the rectum and anus. On the right the mucous membrane has been 

 removed to show the dilatation of the veins and how they pass through the muscular wall to anastomose with the 

 external hemorrhoidal plexus. (Luschka.) 



The lumen of the anal canal presents, in its upper half, a number of vertical 

 folds, produced by an infolding of the mucous membrane and some of the mus- 

 cular tissue. They are known as the rectal columns [Morgagni] (Fig. 1078), and are 



Leucocytes in 

 epithelium 



Gland 



Muscularis 

 mucosce 



Germ-centre 



Solitary lymphatic nodule 

 Fia. 1082. Section of mucous membrane of human, rectum. (Sobotta.) X 60. 



separated from one another by furrows (rectal sinuses), which end below in small 

 valve-like folds, termed anal valves, which join together the lower ends of the 

 rectal columns. 



Structure of the Colon. The large intestine has four coats: serous, muscular, areolar, and 

 mucous. 

 75 



