21G ANATOMY OF THE ABDOMEN, ETC. 



termination, to form the glans penis. The urethra occi 

 pies the centre of the corpus spongiosum. 



The glans, being larger than the surrounding body 

 the penis, forms a projecting u shoulder," called the coroi 

 glandis, which is filled with sebaceous glands, called tl 

 glands of Tyson. It is covered by a delicate mucous mei 

 brane, reflected upon the inner surface of the prepuce, an< 

 continuous with the external skin of the organ. The e: 

 ternal orifice, or meatus of the urethra, opens in the glai 

 by a vertical fissure, and, from the lower end of this, tin 

 mucous membrane forms a fold between the prepuce am 

 the gland, called thefrenum. 



The corpus spongiosum and the corpora cavernosa ai 

 invested by a dense elastic fascia, called the sheath of tli 

 penis. The internal structure of both these bodies and 

 the glans is essentially the same, being composed of whs 

 is called erectile tissue. From the inside of their investing 

 sheaths, fibrous bands, called trabeculae, passing in different 

 directions, divide the whole interior into a multitude of 

 minute spaces, which, upon section, have a spongy aspect, 

 and are more or less filled with venous blood. Within 

 these spaces is an intricate plexus of veins, completely 

 filling them, and with which the arteries, ramifying in the 

 trabeculse, communicate. The blood is received from the 

 branches of the internal pudic artery, and returned by the 

 vena dorsalis, which, joined by short branches entering it 

 upon the upper surface and at the root of the penis, empties 

 into the prostatic plexus. 



The urethra extends from the orifice of the bladder to 

 the meatus of the glans, and is divisible into three portions: 

 prostatic, membranous, and spongy. It should be exposed 

 by laying it open with the scissors along the superior 

 surface. 



The prostatic urethra is surrounded by the prostate, the 

 portion of which lying above the urethra is much thinner 

 than that below. Upon its inferior wall is a small project- 

 ing crest, called the veru montanum, or coput galinaginis ; 

 the depression on each side of this is called the prostatic 

 sinus, the floor of which is perforated by the orifices of the 

 prostatic ducts ; these may be demonstrated by squeezing 

 the prostate; this will force out the secretion through 

 their apertures. At the anterior part of the veru montanum 

 is an opening, called the sinus pocularis, and upon the sides 

 of this the ejaculatory, or seminal ducts, have their opening ; 



