450 ABDOMEN 



municates with the internal pudendal vein, and it becomes 

 continuous above, at the base of the prostate, with the 

 prostatico-vesical venous plexus, from which the blood is 

 drained by the inferior vesical veins. 



Immediately surrounding the prostate, and quite inde- 

 pendent of the sheath, is the fibrous capsule of the prostate. 

 The fibrous capsule varies in thickness, in some cases being 

 extremely thin and in others forming a distinct cortex. In 

 association with operations for the removal of the prostate, 

 now frequently performed, it is important to notice that the 

 capsule has but very slight connection either with the venous 

 plexus or with the sheath of pelvic fascia. It is on that 

 account that the gland can be so easily shelled out from its 

 surroundings. 



The prostate presents for examination a base or superior 

 surface, an apex or inferior extremity, a posterior surface, two 

 lateral surf aces, and an anterior, rounded border. The base looks 

 upwards. It surrounds the internal urethral orifice, and, in a 

 considerable part of its extent, is structurally continuous with 

 the bladder. Around the greater part of its circumference, 

 however, it is separated from the bladder by a groove in 

 which is lodged a group of thin-walled veins, known as the 

 prostatico-vesical plexus. The apex abuts against the upper 

 fascia of the urogenital diaphragm (Fig. 200). The posterior 

 surface is usually a flat triangular area which rests on the 

 anterior aspect of the rectum, but, occasionally, it is marked 

 by a median, vertical groove. The two lateral surfaces rest 

 upon the levatores ani muscles, and are separated from each 

 other by the prominent, rounded, anterior border, from which 

 the urethra emerges immediately above the apex of the gland. 



The delicate ejaculatory ducts pierce the base of the 

 prostate a short distance behind the internal urethral orifice 

 of the bladder, and, as they descend, through the substance 

 of the prostate, they separate the so-called middle lobe from 

 the remainder of the gland, which is generally spoken of as 

 consisting of two lateral lobes, though there is no structural 

 demarcation between them. 



The blood -supply of the prostate is derived from the 

 inferior vesical and middle haemorrhoidal arteries. 



Vesiculse Seminales. The two seminal vesicles lie between 

 the fundus of the bladder and the rectum. Each is about 

 50 mm. (two inches) in length and is piriform in shape. 



