THE PENIS. 1971 



passes. Continuing between the subpubic and transverse ligaments and piercing the 

 fascia, it gains the pelvis and ends, after dividing into two trunks, in the prostatic 

 plexus. Beginning above the corona by the union of two stems that collect branches 

 from the glans and the prepuce,- the deep dorsal vein, as it courses upward, receives 

 tributaries from all three cylinders of erectile tissue. Those from the corpora caver- 

 nosa either pierce the albuginea as short branches that pass directly into the dorsal 

 vein, or emerge from their under surface along the urethral groove and wind around 

 the body of the penis to reach the collecting trunk on the dorsum, the anterior of 

 these circumflex veins taking up tributaries from the under surface of the glans. 

 Within the posterior part of the cavernous bodies are formed the deep veins of the 

 penis, which emerge where the crura diverge and, after establishing communications 

 with the prostatic plexus, become important tributaries of the internal pudic veins 

 that accompany the corresponding arteries. The corpus spongiosum is- drained by 

 anterior branches that convey the blood to the dorsal vein by joining the circumflex 

 or other veins from the corpora cavernosa, and by posterior stems (vv. urethrales) that 

 pass upward and backward and empty partly into the prostatic plexus and partly into 

 the internal pudic veins, the veins from the urethral bulb having a similar destination. 

 Numerous anastomoses between the cutaneous veins and those from the erectile tissue 

 establish free communication between the superficial and deep vessels. 



The lymphatics are numerous and disposed as superficial and deep vessels. The 

 former are tributary chiefly to a superficial dorsal stem that accompanies the cor- 

 responding vein and begins by the confluence of plexiform lymphatics within the 

 integument of the prepuce and frenum. During its course the dorsal trunk receives 

 lymphatics from the adjacent territory as well as others from the under surface that 

 gain the dorsum by following the circumflex veins around the body of the penis. 

 At the pubes the superficial dorsal lymph-trunk passes either to the right or left, or, 

 when double, as it occasionally is, to both or even opposite sides, and joins the 

 median group of superficial inguinal lymph-nodes. Direct communications with the 

 deep subinguinal nodes sometimes exist (Kiittner). The deeper lymphatics are 

 particularly numerous in the periphery of the glans, around the meatus communi- 

 cating with the urethral and preputial plexuses. Trunks are formed which occupy 

 the retroglandular sulcus and unite into a deep dorsal lymph-stem, sometimes double, 

 that accompanies the corresponding vein beneath the fascia and terminates, when 

 single, in the median inguinal nodes of the left side (Marchant). 



The nerves of the penis include both spinal and sympathetic fibres, the former 

 from the ilio-inguinal and the pudic nerves, and the latter from the hypogastric 

 plexus. The integument around the root of the penis is supplied by the cutaneous 

 branches of the ilio-inguinal and the inferior pudendal nerves, while that of the body 

 and the prepuce is provided with the cutaneous branches of the dorsal nerves. The 

 cylinders of cavernous tissue also receive twigs from the pudic nerves, the bulbar 

 branches of which pass to the bulbus urethra? and in addition supply the mucous 

 membrane of the urethra. Each corpus cavernosum receives a deep branch from the 

 dorsal nerve which is given off as the latter lies between the layers of the triangular 

 ligament. The sympathetic fibres destined for the blood-vessels and muscle of the 

 erectile tissue are continued from the hypogastric plexus through the prostatic plexus 

 to the plexus cavernosus, where, joining the dorsal nerves of the penis, twigs (oervi 

 cavernosi penis minores) are sent to the posterior part and the crura of the corpora 

 cavernosa, while others (nervi cavernosi penis majores) are distributed to the lower 

 portions of the erectile masses, some fibres terminating within the spongy body. 

 Close net-works of non-medullated fibres have been traced within the bundles of invol- 

 untary muscle of the blood-vessels and trabeculae of the erectile tissue. Certain 

 cerebro-spinal fibres (nervi erigentes) supposed to be especially concerned in erection 

 are conveyed, in company with the sympathetic fibres, along the paths of the cavernous 

 plexus. 



In addition to a generous supply of the more usual nerve-terminations, the skin 

 of the glans and the prepuce is provided with special nerve-endings, the tactile 

 bodies and the genital corpuscles of Krause (page 1017) lying within the papillce and 

 the Pacinian corpuscles within the subcutaneous stratum. The paths of the sensory 

 impressions lie within the dorsal nerves. 



