380 CLINICAL APPLIED ANATOMY. 



between the lymphatics of the appendix and those of the 

 right ovary has been described but needs confirmation. The 

 appendix receives its blood-supply from the appendicular artery. 

 This small vessel is derived from the terminal branch of the 

 superior mesenteric, and usually passes behind the termina- 

 tion of the ileum to reach the meso-appendix. Kunning along 

 the free edge of this fold it distributes a series of branches to 

 the wall of the appendix. The meso-appendix is not continued 

 quite to the tip of the appendix, and where it terminates the 

 appendicular artery continues its course in close apposition to the 

 muscular wall. The base of the appendix also receives twigs 

 from the caecal arteries, and, in the female, the ovarian artery is 

 said to supply a small branch, but, like the intercommunication 

 between the appendicular and ovarian lymphatics, the presence 

 of this is not satisfactorily established. There can be no doubt 

 that the chief factor in the production of gangrene is virulence 

 of inflammation, but it has been supposed that obstruction of 

 the appendicular artery by twists or adhesions may be a con- 

 tributing cause. The great frequency of gangrenous processes 

 near the tip of the organ may be due to the greater ease with 

 which the terminal portion of the appendicular artery is involved 

 by extension of the inflammation, the vessel being here in closest 

 contact with the muscular wall. 



The nerves of the appendix are derived from the superior 

 mesenteric plexus. This plexus consists of branches from the 

 coeliac plexus, the semilunar ganglia, and the vagus. Neverthe- 

 less, the wall of the appendix, like other parts of the intestine, 

 is quite insensitive. Consequently absence of pain in appendicitis 

 does not indicate that serious mischief is not in progress. In 

 the early stages of appendicitis pain is often vaguely referred to 

 the region of the umbilicus. This pain is supposed to be due to 

 the drag exercised by the contracting caecum and appendix on 

 their peritoneal attachments to the posterior abdominal wall, for 

 it is well known that tension on the root of the mesentery or 

 mesocolon can elicit pain of this nature. This supposition is 

 supported by the fact that the umbilical pain soon ceases, 



