THE HUMAN PROSTATE GLAND 305 



Fetus 5 cm. long: 21 {ten weeks) 



A study of the bladder and prostatic portion of the urethra 

 of a human male fetus two and one-half months of age shows 

 several interesting features. The bladder at the trigonal region 

 has about the same circumference as it has over the rest of its 

 area, being at thjs stage a tubular structure which narrows down 

 gradually as it approaches its orifice and nowhere is there a sharply 

 outlined portion which will later become the vesical orifice. The 

 prostatic portion of this tubular structure is marked only by the 

 change in its shape. 



The organs all seem to be composed of embryonic connective 

 tissue which is similar throughout. The walls of the bladder are 

 uniform in size everywhere except in the region of the trigone 

 which is nearly twice as thick as any other portion. The con- 

 nective tissue strands can be traced from the ureters out into the 

 trigone and the latter structure is quite definitely superimposed 

 upon the bladder wall. The increased thickness of the base of 

 the vesical wall extends throughout the trigonal region but is 

 most marked at the beginning or interureteral region. 



By following this gradually narrowing tube down there is 

 noticed a change in shape so that there is a slight notch formed in 

 the ventral wall of the urethra and a projection into the lumen 

 of the posterior wall so that this structure takes on the shape of 

 a very widely spread inverted V. This marks the beginning of the 

 verum montanum. Further down there are noticed two little 

 notches on the floor of the urethra, one on each side of the verum 

 montanum. The one on the right is more pronounced than that 

 on the left. The outer or lateral portions of the lumen which 

 will later become the prostatic furrows point in a horizontal direc- 

 tion and at this period of development show no tendency to be 

 directed downward (fig. 1). 



In no portion of the prostatic urethra is there any thickening of 

 tissue or outgrowth of epithelial cells indicating the development 

 of prostatic gland tissue. There is no specific arrangement of 

 tissue planes and it is not possible to pick out the exact site of the 



* 



21 These measurements are all crown-rump and not crown-heel. 



