868 A MAN-UAL OF ANATOMY 



Blood-supply — Arteries. — These are as follows : (i) superior 

 vesical, from the pervious portion of the obliterated hypogastric ; 



(2) inferior vesical, from the anterior division of the internal iliac ; 



(3) vesical, from the intrapelvic portion of the obturator ; (4) vesical, 

 from the intrapelvic portion of the sciatic ; and (5) branches from 

 the uterine and vaginal arteries in the female. 



Veins. — These are very copious, and are arranged in two plexuses 

 — superior vesical and prostatico-vesical. The vesical plexus 

 is situated over the fundus and sides of the bladder, and its 

 blood is conveyed into the prostatico-vesical plexus. The pros- 

 tatico-vesical plexus is composed of two parts, continuous with each 

 other, namely, vesical and prostatic. The vesical portion surrounds 

 the neck of the bladder, and its blood is conveyed by one or more 

 vesical veins into the internal iliac vein. 



Lymphatics. — ^These pass to the external and internal iliac glands. 



Nerves. — Each half of the bladder receives sympathetic and spinal 

 fibres from the following sources : (i) the pelvic plexus of the sym- 

 pathetic, which contains spinal fibres from the third and fourth 

 sacral nerves (sometimes also from the second), these being known 

 as the pelvic splanchnics ; and (2) special twigs from the pelvic 

 splanchnics, which can be traced independently to the bladder. It 

 is to be noted that the bladder also receives spinal fibres from the 

 upper two or three lumbar nerves through the intervention of 

 {a) the ganglia of the lumbar sympathetic cord, {h) the aortic 

 plexus, (c) the hypogastric plexus, and {d) the pelvic plexus. 



Structure of the Penis. 



Corpora Cavernosa. — Each corpus cavernosum has a strong 

 capsule, called the tunica albuginea. This tunic is composed of 

 fibrous, plain muscular, and elastic tissues. It is disposed in two 

 laminae — external and internal. The fibres of the external lamina 

 are arranged longitudinally, and are common to both corpora 

 cavernosa. The fibres of the internal lamina run circularly round 

 each corpus cavernosum, and in the middle line those of each side 

 meet and are prolonged inwards as a septum, which is imperfect 

 except near the roots of the penis, being traversed by vertical clefts. 

 This partition is called the septum pectiniforme. From the inner 

 surface of the tunica albuginea strong trabeculae are given off, 

 which penetrate into the interior of the corpus cavernosum. These 

 trabeculae, which are fibro-muscular and elastic in character, are 

 arranged in a reticular manner, and enclose the cavernous spaces of 

 the erectile tissue. The artery of the corpus cavernosum lies in the 

 centre, and, in addition to this chief vessel, several other arteries, 

 derived from the dorsal artery of the penis, enter it from the surface. 

 The branches of these arteries run in the trabeculae, and terminate 

 in capillaries, which pour their blood directly into the cavernous 

 or intertrabecular spaces. Some of the small arteries in the trabe- 

 culae are thrown into spiral loovs, which project into the intertra- 



