182 VISCERAL ANATOMY. 



Where do their Ducts open ? On the floor of the bulbous part of the 

 spongy portion of the urethra, after traversing the wall of the urethra for about 

 one inch, between its mucous and muscular coats. 



THE PENIS. 



Of what is the Penis composed ? Of a mass of erectile tissue arranged 

 in three compartments of cylindrical shape, each surrounded by a fibrous 

 sheath which is prolonged inwards, forming numerous bands (trabeculae), 

 which divide the compartment into a number of spaces. The compartments 

 are named the Corpora Cavernosa l and the Corpus Spongiosum, 2 the latter 

 lying between and beneath the former, like the ramrod of a double barreled 

 gun. 



Describe the Corpora Cavernosa. ( 19 , Fig. 89.) They lie side by 

 side, forming the upper and lateral parts of the 

 penis, are joined together along their anterior 

 three- fourths, their posterior one-fourth form- 

 ing the Crura, which arise from the tuberosi- 

 ties of the ischia and their descending rami, 

 and meet beneath the symphysis pubis, forming 

 two grooves, one above for the dorsal vessels 3 , 

 4 and nerves, 5 the inferior one for the corpus 

 spongiosum. 2 



Bulb of the Corpus Cavernosum, is a slight 

 enlargement on each crus, near its junction with its fellow. 

 Suspensory Ligament, a fibrous membrane which connects the root of the 



organ to the symphysis pubis. 



Septum Pectiniforme, is a portion of the fibrous septum between the corpora 

 cavernosa. This septum extends but two-thirds along the penis, and is 

 wanting for its anterior third. 



Describe the Corpus Spongiosum. It is an erectile tube lying in the 

 inferior groove between the two corpora cavernosa, having within it the 

 urethra, and being expanded at both ends to form the glans penis and the 

 bulb. It is composed of trabecular (band-like) structure, derived from a 

 fibrous sheath, and containing erectile tissue. The 



Bulb of the Corpus Spongiosum, receives the urethra and is surrounded by 



the accelerator urinae muscle. 



Glans Penis, is the external expansion of the corpus spongiosum, and 

 covers by its base the ends of the two corpora cavernosa. Its base pre- 

 sents a rounded border, called the Corona Glandis, behind which is a 

 deep sulcus, the Cervix. 



