854 



A MANUAL OF ANATOMY 



tinuous in front of and behind the prostatic portion of the urethra. 

 The middle lobe represents that part of the basal portion of the 

 gland which is wedged in between the CDmmon ejaculatory ducts 

 and the adjacent portion of the neck of the bladder, and which 

 lies just below the apex of the internal trigone. It is important to 

 note that the middle lobe lies behind the commencement of the 

 urethra. It is liable to become hyper trophied in old age, and 

 then it may produce undue elevation of the uvula vesicae in the 

 interior of the bladder, which is a natural product of it. In this 

 manner, by blocking the urethral orifice, it may not only give rise 

 to difficulty in micturition, but may also obstruct catheterization. 



The prostate gland is traversed by the first ij inches of the 

 urethra. The common ejaculatory ducts are also contained within 

 the gland, in which they pass downwards and inwards between the 

 middle and lateral lobes. For the structure and development of 

 the prostate gland, see Index. 



Urethra. — ^The male urethra commences at the urethral orifice 

 in the neck of the bladder, and terminates at the extremity of the 



Urachus 



Vesicula Seminalis 



Vas Deferens 



* Cowper's Gland 



Fig. 368. — Section of the Bladder and Penis to show the Urethra. 



glans penis in a vertical fissure, called the meatus urinarius. It 

 is about 8 inches in length, and is divided into three portions, 

 which, from the bladder outwards, are called prostatic, membranous, 

 and spongy. The prostatic and membranous portions constitute 

 the non-penile part of the canal, and the spongy portion, being 

 contained within the corpus spongiosum of the penis, represents 

 the penile part. 



The prostatic portion of the urethra is the part of the canal 

 which is contained within the prostate gland. It is ij inches in 

 length, and its course is almost vertical, there being a slight curve 

 with the concavity directed forwards. It is spindle-shaped, being 

 wider at the centre than at either end, and at its upj^er or vesical 



