CORPUS SPONGIOSUM. 435 



more than arterial loops or convolutions thrown into peculiar forms 

 by the manner in which they are bound down by the trabeculge in 

 which they run. They are most distinct in man, but are not con- 

 stant in animals, so that, whatever may be their use, they do not appear 

 to be essential to the process of erection. 



According to Langer the deep arteries of the corpora cavernosa, pene- 

 trating by the side of the septum, and dividing within the trabeculse, 

 terminate in the following several ways : 1st, over the whole surface of 

 the corpora cavernosa and close to the fibrous sheath and septum, they 

 form by their division true capillaries which communicate with the 

 deeper cortical venous network ; 2nd, into this network there also open 

 directly arterial twigs of about ^ j o^h of an inch in diameter, without any 

 intermediate capillary division ; and 3rd, arterial vessels of from :;^oth to 

 3-^-oth of an inch in diameter open, without the intervention of capil- 

 laries, into the larger venous spaces of the interior. Capillary networks 

 also surround the arterial branches and the trabeculfe of the deeper 

 parts of the corpora cavernosa. (C. Langer, in Sitzuugsbericht der 

 Wien. Acad., vol. xlvi. p. 120.) 



CORPUS SPONGIOSUM. 



The corpus spongiosum uretJircb commences in front of the triangular 

 ligament of the perineum, where it is placed between the diverging crura 

 of the corpora cavernosa, and somcAvhat behind their point of junction. 

 The enlarged and rounded posterior extremity is named the huJb, and is 

 situated below the urethra. It extends forwards as a cylindrical, or 

 slightly tapering body, lodged in the groove on the under side of the 

 united cavernous bodies, as far as their blunt conical anterior extremity, 

 over which it expands so as to form the glans penis already described. 

 In the whole of this extent it encloses the urethra. 



The posterior bulbous part, or lull) of the urethra., varies in size in 

 different subjects. It receives an investment from the triangular liga- 

 ment on which it rests, and is embraced by the accelerator urinte, or 

 bulbo-cavernosus muscle. The posterior extremity of the bulb exhibits, 

 more or less distinctly, a subdivision into two lateral portions or lobes, 

 separated by a slight furrow on the lower surface, and by a slender fibrous 

 partition within, which extends for a short distance forwards ; in early 

 infancy this is more marked. It is above this part that the urethra, 

 having pierced the triangular ligament, enters the bulb, surrounded 

 obliquely by a portion of the spongy tissue, named by Kol3elt the coUir- 

 culus hulhi, from which a layer of venous erectile tissue passes back 

 upon the membranous and prostatic portions of the urethra to the 

 neck of the bladder, lying closely beneath the mucous membrane. At 

 first the urethra is nearer the upper than the lower part of the corpus 

 spongiosum, but it soon gains and continues to occupy the middle of 

 that body. 



Structure. — This is essentially the same as regards the vascular part 

 with that of the corpora cavernosa, but with a much less quantity of the 

 external fibrous and deeper trabecular structure. Like the corpora 

 cavernosa, it is distended with blood during erection, but never acquires 

 the same rigidity. The outer fibrous tunic is much thinner, is less white 

 in colour, and contains more elastic tissue ; the areolfB are smaller, and 

 directed for the most part with their long diameter in the line of that 



F F 2 



