128 THE BLADDER AND URETERS, BY HEINRICH OBERSTEINER. 



definite, running parallel to each other, and forming a complete 

 ring at the orifice of the bladder, the sphincter vesicse. Ex- 

 ternally to this circular layer follows the layer composed of 

 longitudinal fasciculi, which gradually predominates towards 

 the vertex, and in children may be observed to be continued 

 into the partially or completely obliterated urachus. It is im- 

 possible to give more minute details respecting the course of 

 the muscles, since, in the various bladders I have examined, 

 the variations have been so great that a minute description is 

 only applicable to the individual specimen. 



The Trigonum lieutodii consists merely of a thickening of 

 the connective tissue with all its elements, extending from the 

 orifices of the ureters to the Caput gallinaginis. 



The vessels of the bladder, the Arteria vesicalis superior and 

 inferior, proceeding from the posterior wall of the Arteria 

 hypogastrica, are chiefly distributed to the fundus. They 

 penetrate the muscular layer of this part obliquely, giving off 

 a few small branches to it as they traverse it, and are 

 distributed in the connective-tissue layer about midway 

 between the epithelium and the muscular tissue, and nearly 

 parallel to the surface. From these trunks small branches 

 ascend vertically towards the epithelium, immediately beneath 

 which, separated only by a layer of fibrous tissue that is 

 sometimes scarcely perceptible, they form a close and delicate 

 capillary plexus. If the bladder be thrown into folds, these 

 small branches occupy the middle of the fold, and are thus 

 preserved from angular bends and curves. 



The nerves may be followed as medullated fibres in the 

 connective-tissue layers, especially at the fundus near the 

 urethral orifice, where they are present in great numbers. It 

 is difficult to form a correct judgment on their mode of termi- 

 nation. Kisselew considers that they end in peculiar cells of 

 the epithelial layer, distinguished from the rest by their 

 becoming more strongly tinted with carmine, and by their 

 firmer adhesion to the subjacent connective tissue. He seems, 

 however, only to have had objects similar to the migrating 

 cells under observation. A few ganglion cells are found, 

 though only very sparingly, in the course of the nerves. 



Medullated nerve fibres can be beautifully followed in the 



