THE PKOSTATE. 



1301 



The veins with which the cavernous spaces communicate, carry the blood, for the most part, 

 either directly into the pudendal plexus, or into the dorsal vein and so to the pudendal plexus. 

 The dorsal vein of the penis begins in tributaries from the glans and prepuce, and lies in the 

 groove between the corpora cavernosa penis as it ascends to pass beneath the arcuate ligament 

 of the pubis to join the pudendal plexus. On each side of it lies the dorsal artery, and still 

 farther from the median plane lies the dorsal nerve (Fig. 1019). 



The lymph.- vessels of the penis are arranged in a deep and superficial series, and end in the 

 medial glands of the inguinal group of lymph -glands. 



The nerve-supply of the penis is derived from the pudendal nerve and from the hypo- 

 gastric and pelvic plexuses. The branches of the pudendal are the dorsal nerve of the penis, 

 and branches from the perineal nerves. These supply the cutaneous structures of the penis, 

 while the sympathetic filaments from the hypogastric and pelvic plexuses, which reach the 

 penis through the prostatic nerve plexus, end in the erectile tissue. 



PROSTATA. 



The prostata, or prostate, is a partly glandular, partly muscular organ of a dark 

 brown-red colour which surrounds the beginning of the urethra in the male. It 

 lies within the pelvis' behind the pubes, and is enclosed by a dense sheath derived 

 from the pelvic fascia. Through the various connexions of this sheath the 

 prostate is firmly fixed within the pelvic cavity. The ejaculatory ducts traverse 

 the prostate in their course downwards and forwards to join the urethra as it 



Superior surface 

 of bladder 



Lig. urn- Seiuma 

 bilieale vesicle 

 medium 



Infero-lateral 



area of bladder 



Lateral 

 aspect of 

 prostate 



ral aspect 

 of prostate 



.Urethra 



edian 

 umbilical 

 ligament 

 (urachus) 



Infero-lateral 

 area of bladder 



Urethra 



FIG. 1021. URINARY BLADDER, PROSTATE, AND SEMINAL VESICLES VIEWED FROM THE SIDE. 

 Drawn from specimens hardened in situ. 



nds through the gland (Fig. 1023). The size of the prostate varies con- 

 siderably in different individuals, but its transverse, or longest, diameter is usually 

 from one and a quarter to one and a half inches; its an tero- posterior diameter 



: about three-quarters of an inch ; and its vertical diameter about one and a quarter 

 inches. Superficially the prostate is separated from the bladder by deep wide 



; lateral grooves directed downwards and forwards, and by a narrow posterior groove 

 which is horizontal. 



In connexion with the prostate we describe an apex which is directed down- 



; wards, a base looking upwards, a posterior, and two lateral surfaces. The general 

 outline of the organ has been often compared with that of a Spanish chestnut. 

 The upper surface, or basis prostatse, is directed upwards against the inferior aspect 

 of the bladder, in the neighbourhood of its urethral opening. The greater part of 

 this surface is structurally continuous with the bladder wall, only a narrow portion 

 remains free on each side, and forms the lower limit of the deep groove which 

 marks the separation of the bladder and prostate (Fig. 1021). The lateral surfaces 

 of the prostate are convex and prominent, especially in their posterior and upper 

 portions, and rest against the fascia covering the levator ani muscle. They are 



' directed for the most part laterally, downwards, and somewhat forwards, and meet 

 together in front in a rounded anterior border, sometimes called the "anterior 



; surface," or " facies anterior," of the prostate. Posteriorly the prostate presents a 

 flattened somewhat triangular posterior surface, directed backwards and downwards 



