CORPORA CAVERNOSA PENIS. 



529 



terminate, one on each side, on the floor of the urethra near the front of 

 the bulb, but they are generally too small to be recognized. 



Mucoiis lining of the urethra. The mucous membrane of the urethra 

 is continued into the bladder, as well as into the ducts opening into the 

 canal, and joins in front the tegumentary covering of the glans penis. It 

 is of a reddish color in the spongy and membranous portions, but in the 

 prostate it becomes whiter. In the spongy and membranous parts it is 

 thrown into longitudinal folds during the contracted state of the penis. 



Its surface is studded throughout with follicles, and with the apertures 

 of branched glands, which are lodged in the submucous tissue, and whose 

 ducts are inclined obliquely forwards ; and it is provided with papillae to- 

 wards the external orifice. Its epithelial covering is of the columnar kind, 

 but near the meatus it becomes laminar. 



Submucous tissue. Beneath the mucous lining of the urethra is a 

 stratum of longitudinal unstriated muscular fibres, mixed with elastic and 

 fibrous tissues. It is continuous behind with the submucous fibres of the 

 bladder, and is joined in the prostate by the muscular fibres accompanying 

 the common seminal ducts. The stratum differs along the canal : It is 

 most developed in the prostate, where it forms the projection of the crest ; 

 in the membranous portion the muscular structure is less abundant ; and 

 in the spongy part fibrous tissue forms the greater portion of the submucous 

 layer. 



In the prostatic and membranous divisions of the urethra there is, in 

 addition, a thin enveloping layer of vascular or erectile tissue, which is 

 continued backwards 1'rorn the corpus spongiosum urethra? to the neck of 

 the bladder. 



STRUCTURE OF THE PENIS. The form and the connections of the penis 

 having been described in page 508, the tissues of which it is composed 



Fig. 182. 



VIEW OF THB FIBRES OF THE CASE OF THE CORPCS CAVERNOSCM. 

 b. The external or longitudinal layer. 1. The pectiniform septum. 



a. Inner or circular fibres. 



remain to be noticed. If a section is made along one side of the pen's, it 

 will show this body to be composed of two masses of spongy and va$cu)ar 

 tissue (corpora cavernosa) incased in a h'brous covering, with an imperfect 

 septum between them. 

 34 



