406 



DISSECTION OF THE PELVIS. 



Prostate 

 gland : 



situation ; 



form; 

 dimensions ; 



and weight. 

 Surfaces ; 



base; 

 and apex. 



Three lobes, 

 two lateral, 



and a cen- 

 tral, 



often 

 enlarged. 



Gland con- 

 tains three 

 tubes. 



Structure. 



Muscular 

 fibres are 

 plain 



circular, 



radiating, 



THE PROSTATE GLAND AND SEMINAL VESICLES. 



PROSTATE GLAND (fig. 151, p. 408). This is a firm muscular 

 body containing glands, which surrounds the neck of the bladder 

 and the beginning of the urethra. Its relations have already been 

 enumerated at p. 388. 



The prostate is conical in form, like a chestnut, with the base 

 directed upwards. Its dimensions are the following : Trans- 

 versely at the base it measures about an inch and a half ; from 

 apex to base an inch and a quarter ; and from before backwards about 

 three-quarters of an inch or an inch : so that an incision directed 

 obliquely outwards and backwards will be the longest that can be 

 practised in the half of this body. Its weight is about an ounce, 

 but in this respect it varies greatly. 



The anterior surface of the prostate is narrow and rounded. The 

 posterior surface, larger and flatter, is marked by a median hollow 

 which indicates the division into lateral lobes. 



The base is thick, and at its posterior part has a median notch, 

 which receives the common seminal ducts. The apex is pierced by 

 the urethra. 



Three lobes are described in the prostate, viz., a middle and two 

 lateral, though there is no fissure in the firm mass. The lateral 

 lobes (fig. 151, 6, c) are similar on the two sides, and are separated 

 only by the hollow on the under surface ; they form the chief part 

 of the prostate, and are prolonged back, on each side, beyond the 

 notch in the base. The middle lobe (d) will be brought into view 

 by separating the vesiculse seminales and the vasa deferentia from 

 the bladder : it is the piece of the gland between the neck of the 

 bladder and the seminal ducts, which extends across between the 

 lateral lobes. Oftentimes the middle lobe is enlarged in old 

 people, and projects upwards into the bladder, so as to interfere 

 with the flow of the urine from that viscus, or the passage of a 

 catheter into it. 



The urethra and the two common seminal ducts are contained 

 in the substance of the prostate as will be seen immediately. The 

 former is transmitted through the gland from base to apex ; and 

 the latter perforate it obliquely to terminate in the urethral canal. 



Structure. On section the prostate appears reddish grey in colour, 

 is very firm to the feel, and is scarcely lacerable. It is made up 

 of a mass of muscular and fibrous tissues, with interspersed glandu- 

 lar substance ; and the whole is enveloped by strong proper capsule 

 and is surrounded by a fibrous sheath derived from the recto-vesical 

 fascia, which is sometimes styled the false capsule. 



Muscular tissue. The firm mass of this body consists mainly of 

 involuntary muscular fibres, intermixed with elastic and fibrous 

 tissues. One set of muscular fibres is arranged circularly round 

 the urethral canal, these are continuous above with the annular 

 fibres of the bladder, and below with a thin layer of circular fibres 

 surrounding the membranous portion of the urethra ; others run 

 transversely behind the urethra, and radiate in each lateral lobe 



