THE MALE URETHRA. 1147 



over the posterior part of the membranous portion of the urethra, and as it pierces 

 the anterior layer, a similar prolongation takes place in the opposite direction, 

 investing the anterior part of the membranous portion. It is also surrounded by 

 the Compressor urethrse muscle. 



The Spongy portion is the longest part, and is contained in the corpus spongi- 

 osum. It is about six inches in length, and extends from the termination of the 

 membranous portion of the meatus urinarius. Its direction at first is downward and 

 forward then upward for a short distance and then downward again. It is narrow 

 and of uniform size in the body of the penis, measuring about a quarter of an inch 

 in diameter, being dilated behind, within the bulb, and again anteriorly within the 

 glans penis, where it forms the fossa navicularis. 



The Bulbous portion is a name given, in some descriptions of the urethra, to 

 the posterior part of the spongy portion contained within the bulb. 



The meatus urinarius is the most contracted part of the urethra ; it is a vertical 

 slit, about three lines in length, bounded on each side by two small labia. 



The inner surface of the lining membrane of the urethra, especially on the floor 

 of the spongy portion, presents the orifices of numerous mucous glands and follicles 

 situated in the submucous tissue, and named the glands of Littre. They vary in 

 size, and their orifices are directed forward, so that they may easily intercept the 

 point of a catheter in its passage along the canal. One of these lacunae, larger than 

 the rest, is situated in the upper surface of the fossa navicularis, about an inch and 

 a half from the orifice ; it is called the lacuna magna. Into the bulbous portion 

 are found opening the ducts of Cowper'a glands. 



Structure. The urethra is composed of a continuous mucous membrane, 

 supported by a submucous tissue which connects it with the various structures 

 through which it passes. 



The niuci'iu* coat forms part of the genitourinary mucous membrane. It is 

 continuous with the mucous membrane of the bladder, ureters, and kidneys; 

 externally with the integument covering the glans penis ; and is prolonged into 

 the ducts of the glands which open into the urethra viz. Cowper's glands and the 

 prostate gland and into the vasa deferentia and vesiculae seminales through the 

 ejaculatory ducts. In the spongy and membranous portions the mucous membrane 

 is arranged in longitudinal folds Avhen the organ is contracted. Small papillae 

 are found upon it near the orifice, and its epithelial lining is of the columnar and 

 stratified variety, excepting near the meatus, where it is squamous. 



The submucous tissue consists of a vascular erectile layer, outside which is a 

 layer of unstriped muscular fibres, arranged in a circular direction, which sepa- 

 rates the mucous membrane and submucous tissue from the tissue of the corpus 

 spongiosum. 



Surgical Anatomy. The urethra maybe ruptured by the patient falling astride of any 

 hard substance and striking his perinaeum, so that the urethra is crushed against the pubic arch. 

 Bleeding will at once take place from the urethra, and this, together with the bruising in the 

 perinaeum and the history of the accident, will at once point to the nature of the injury. 



The surgical anatomy of the urethra is of considerable importance in connection with the 

 passage of instruments into the bladder. Otis was the first to point out that the urethra is 

 capable of great dilat ability, so that, excepting through the external meatus, an instrument cor- 

 responding to 1 8 English gauge (29 French) can usually be passed without damage. The orifice 

 of the urethra is not so dilatable, and therefore frequently requires slitting. A recognition of 

 this dilatability caused Bigelow to very considerably modify the operation of lithotrity and intro- 

 duce that of litholapaxy. In passing catheters, especially fine ones, the point of the instrument 

 should be kept as far as possible along the upper wall of the canal, as the point is otherwise very 

 liable to enter one of the lacunae. Stricture of the urethra is a disease of very common occur- 

 rence, and is generally situated in the spongy portion of the urethra, most commonly in the 

 bulbous portion, just in front of the membranous urethra, but in a very considerable number of 

 cases in the penile or ante-scrotal part of the canal. 



