Loe ten 
1114 UROGENITAL SYSTEM. 
branches from the internal pudic and sciatic nerves reach the scrotum from behind, while the 
ilo-inguinal supplies its upper and anterior part. 
THE PENIS. 
The penis is composed chiefly of erectile tissue, and is traversed by the canal 
of the urethra. The surface nearest to which the canal of the urethra lies is 
called the under or urethral surface (facies urethralis); the opposite and more 
extensive aspect is the dorsum penis. The erectile tissue is for the most part 
disposed in three longitudinal columns, which in the body of the organ are placed 
side by side, while at the root of the penis they stl from one another, and 
become attached to the triangular ligament and pubic arch. Two of these masses 
of erectile tissue, placed one on each side of the middle line, and forming the 
dorsum and sides of the penis, are called the corpora cavernosa (corpora cavernosa 
Corpus Cavernhosul 
Corpus spongiosum 
Crus penis 
Bulbus urethree 
Tuber ischii 
es 
Fic. 761.—DIssEcTION TO ILLUSTRATE THE COMPONENT PARTS OF THE PENIS. 
On the right side of the figure the muscles of the thigh have been reflected down to the plane of the obturator 
externus. The letters TL are placed upon the triangular ligament. | 
penis), while the third, which is called the corpus spongiosum (corpus cavernosum _ 
urethree), is situated mesially near the urethral surface. The corpus spongiosum is _ 
the part of the penis which is traversed by the urethra, and it is considerably 
smaller than the corpora cavernosa which form the chief bulk of the organ. ) 
In the body of the penis (corpus penis) each corpus cavernosum is placed close — 
to the mesial plane, and presents a rounded surface, except where it is flattened — 
and in contact with its fellow of the opposite side. The corpora cavernosa are 
separated on the anterior (dorsal) surface by a shallow groove, and on the posterior — 
(urethral) aspect by a deeper and wider furrow, in which lies the corpus spongiosum 
(Fig. 762). Towards the distal end of the penis the corpus spongiosum becomes _ 
expanded, and, spreading towards the dorsal surface of the organ, forms a kind of — 
conical cap which covers over the blunt rounded terminations of the corpora 
cavernosa. The terminal expansion of the corpus spongiosum is termed the glans 
penis, and is traversed by the urethra. The prominent margin of the glans, called 
the corona glandis, projects dorsally and laterally beyond the extremities of the 
corpora cavernosa. The slit-like opening at the summit of the glans, where the 
urethra terminates, is termed the meatus urinarius, or external urethral orifice, 
