1250 



URETHRA. 



lacerated, and pour out a large quantity of 

 blood. They have no communication with the 

 veins of the corpus spongiosum itself, properly 

 so called. 



The colour of the mucous membrane de- 

 pends on the degreee of vascularity in dif- 

 ferent parts. Thus, at the meatus, it is of a 

 pink aspect, becoming gradually pale towards 

 the bladder. But in the membranous por- 

 tion, owing to congestion in the veins, it is 

 very frequently much darker, as these vessels 

 are readily distinguishable through the mem- 

 brane, whilst in the prostatic part it is white. 

 The colour of the mucous membrane is much 

 heightened under inflammation : this is espe- 

 cially visible in the fossa navicularis, and at 

 the orifice in severe attacks of gonorrhoea; 

 and the same has been witnessed in other 

 parts of the canal after division of the urethra, 

 during an attack of gonorrhoea. Under in- 

 flammation it loses its smooth, polished aspect, 

 and presents a velvety appearance. 



Mr. Quekett has lately made some beautiful 

 injections of the vessels of the mucous mem- 

 brane of the urethra, in which it is seen that, 

 in the bulbous portion, the bloodvessels run- 

 ning in the vallecula3 between the columns are 

 larger and more numerous than those of the 

 columns themselves ; whilst nearer the meatus, 

 where the columns are either small or alto- 

 gether absent, the membrane is not unfre- 

 quently provided with villi, which resemble 

 those of the lips and extremities of the fingers 

 and toes in having each a single looped capil- 

 lary. 



Lacunte. The whole of the urethra, ex- 

 cept the prostatic portion, is marked by minute 

 openings, distinctly perceptible at the upper 

 and under surface, but they are certainly larger 

 and more numerous on the upper. They are 

 the openings of the lacuna or mucous glands, 

 whose office it is to secrete a bland fluid for 

 the lubrication of the canal, and thus to facili- 

 tate the onward progress of the contents of 

 the urethra. The lacuna? vary in different 

 individuals in size and number : some anato- 

 mists believe them to be more numerous in 

 the membranous portion : my own observa- 

 tions would lead me to the conclusion, that 

 the greater number are to be found in the 

 spongy portion. They are termed indiscrimi- 

 nately the glands of Littre and Morgaeni, or 

 the orifices are called the lacunas of Morgagni, 

 whilst the crypts opening into them are termed 

 glands of Littre. The lacunas vary in depth : 

 in some situations they admit the passage of 

 bristles, to the depth of two or three lines; in 

 others they are by no means so deep, whilst 

 in other cases they are scarcely perceptible. 

 Their orifices face for the most part obliquely 

 forwards towards the meatus, but now and 

 then they pass vertically to the surface; they 

 are found between and upon the columns of 

 the urethra. A simple examination of the 

 lacunae would represent them as mere in- 

 flexions of the mucous membrane of the 

 urethra, and many of the smaller ones are of 

 this nature : some, however, present a cellular 

 appearance, but this seems to arise from the 

 anastomosis of vessels distributed on them : 



they are lined with epithelium of a character 

 similar to that lining the urethral membrane 

 generally, and a considerable plexus of vessels 

 is distributed around them. Under inflamma- 

 tion they pour out a copious secretion, and 

 are not unfrequently the seat of special disease. 

 The use of the lacunae is to extend the secret- 

 ing surface of the mucous membrane of the 

 urethra, in situations where any glandular ap- 

 paratus would have been obviously incon- 

 venient. 



In old cases of stricture, and other diseases 

 of the canal, they become exceedingly enlarged. 



The lacuna magna. Near the termina- 

 tion of the urethra, and within a few lines of 

 the meatus urinarius, will be seen an inflexion 

 of the urethral membrane, forming a cul-de-sac^ 

 into which the b unt end of a probe can be 

 passed : this is denominated the lacuna magna, 

 being in structure and function analogous to 

 the other lacunae of the urethra. The lacuna 

 magna is a point in the anatomy of the urethra 

 of some practical import, inasmuch as it is 

 likely to arrest the entrance of a catheter, 

 and to convey to the ignorant an erroneous 

 idea of stricture. It varies in situation in 

 different individuals. It is usually placed at 

 about one-third of an inch from the meatus 

 on the dorsal aspect of the fossa navicularis, 

 so that, on separating the lips of the meatus, 

 it can D3 brought into view; but it is occa- 

 sionally further back, and now and then is 

 placed on the under surface, and in many 

 cases I have in vain tried to find it. I believe 

 it is occasionally altogether absent. It will 

 be found, where the columns of the urethra 

 are developed, that they take their course 

 towards the lacuna, and, on reaching it, pass 

 off in slender processes to the meatus. In 

 an urethra which I recently examined, I 

 found a lacuna magna of considerable size 

 in the under surface of the urethra, behind 

 the middle of the spongy body. Into this the 

 point of a catheter could be readily passed, 

 and it might have been easily mistaken for 

 stricture. 



Hunter, and most of his successors, believe 

 the matter of gonorrhoea to be incubated in 

 the lacuna magna. 



Structure. The urethral membrane is divi- 

 sible into two distinct layers. The inner, 

 which is analogous to other mucous surfaces, 

 consists of a basement membrane covered 

 throughout by epithelium. This, according to 

 Quain and Sharpey, for the most part, is of 

 the scaly character, but in the vicinity of the 

 bladder it is spheroidal. Henle describes 

 the fossa navicularis as covered with small 

 flat and roundish scales, whilst the remaining 

 part of the urethra is covered with a single 

 series of prismatic particles.* 



Beneath the mucous membrane there is a 

 layer composed of a tissue or structure of a 

 mixed character, containing some contractile 

 fibres, supposed to be muscular, blended with 

 elastic tissue. It is connected to the delicate 

 tendinous covering of the corpus spongiosum, 

 and is supported by transverse tendinous 

 bands distinctly visible beneath it. This layer 

 * See article Mucous MEMBRANE. 



