GENERATION. 



The canal is divided into thtse portions, diftinguinied 

 from each othei by their orjjanization. The firtt, of about 

 an inch in length, which pafTes thro ugli the j)rofLate, has re- 

 ceived no name ; the fecoiid, of about equal extent, conti- 

 nued from the prollate to the buib, is called the membranous 

 portion ; the latter correfponds above to the inferior fur- 

 face of the fymphyfis pubis, but is about half or three 

 quarters of an inch below the bone. Below it is connefied 

 by cellular fu'oflance to the furface of the reftum, and at the 

 fides, th'.? front edges of the levatorcs ani are in contaA with 

 it. This part of the canal has been called the membranous 

 portion, from a notion that the membrane of the uretlira was 

 covered here by no external inveflment, but in faft it is 

 clofely furrounded by a thick ftratum of mufcular fibres. 

 The moH interior of thefe are circular, and lie clofe upon 

 the membrane of the urethra. Mr. Wilfou h.as lately 

 defcribed fome fibres, arifing by a double tendon from tlie 

 arch of the pubes, defcending on each fide of the urethra 



the bull), 7-2Cths; in the middl;; of the proftate ii-2otns; 

 at the neck of the bladder g-zoths. Home on Strictures., 

 vol. i. p. ■,;4, and 2j. 



The fitualion of the eminence, on which the cjaculatorr 

 du3s open, called the vera montanum, in the proftatic part of 

 the urethra, and its figure, have been already noticed ; as well 

 as the opcninj^o of the prolhitic dufts in the fame part of the 

 canal. In the icli of its extent, the internal furface of the 

 canal pofieffes a reddifli colour In the membranous and 

 fpongy portions, longitudinal folds are obfervsble, diiap- 

 pearing on extenilon. Thefe are not feen in the proftate^ nor 

 at the gl^ins, becaufe the firm texture of the parts which ad- 

 here fo very clofely to the mucous membrane, keeps it con- 

 ftantly fmooth. Hence the diameter of thefe parts is nearly 

 uniform at all times. The fides of the canal exhibit-openings 

 of numerous fmall oblique duels, frequently named after 

 Morgagni. Thefe are only feen in that part of the urethra 

 ' ich is in front of the bulb, and are fometimes cnlled 



wliicli is m 



.nnd united under the canal. (Seethe Medico-chirurgical lacunx ; their number and fize vary indifferent fubjecls. 



'.'ranfaftions, vol. i.) Thefe fibres are conneftcd in front with They run from behind forwards, and terminate by l^mple 



■.'.-.i accelerator urinre, and behind with the levatores ani. oblique orifices. Th.ey are ahvays very numerous about the 



They will comprefs the canal when they contract, and, by foffa navicnlaris, from wliich fome have explained the cir- 



clofing it at the time of emifiion, will prevent the feir.inal fluid cumilance of this part being particularly afi'eftcd in gonor- 



from. being driven backwards by the aftion of the accelerator, rhoea. They confiit of (hort canals, formed in the membra- 



The third portion of the urethra, including all the reft ot 

 the canal, is called the fpongy part. It begins by an ob- 

 long rounded portion, named the bulb of the urethra. This 

 is fituated below the union of tlie crura penis, between 

 which it makes a remarkable prominence. Below, and on 

 the fides, it is covered by the accelerator urinas (fee AcCE- 

 xerator), and by Cowper's glands. Together with the 

 two precedirtg parts of the canal, the bulb forms the firlt 

 curvature of the uretlu'a, and its fides are ftrongly connefted 

 to the arch of the pubis by means of a fibrous expanfion, 

 termed the triangular ligament, of- the urethra. The latter 

 part poffefles the figure, which its name indicates ; the bafe 

 of the triangle is turned downwards, the apex upwards, 

 ccrrelponding to the junftion of the ofia pubis, and the fides 

 are attached to the rami of tl^t^ pubes. It is perforated by 

 the paffage of the urethra, which it holds firmlv in its re- 

 ' ive fituation to the bone. In the reft of its extent, the 

 vngy portion of tlie urethra correfponds above to the 

 channel in the under furface cf the corpus cavernofum. Be- 

 lo.v, it is covered near the bulb by the accelerator, then by 

 th.e cellular fubilance of the fcrotum, and afterwards by the 

 integuments of the penis. 



Tiie diameter of the canal is by no means uniform in.its 

 vvhole length. It is large in the middle of the proftate, and 

 fmallcr where it enters and leaves the gland. The canal is 

 liere rather flattened laterally. In the membranous portion 

 it is jierfedliy cylindrical, but fmall in its fize ; and the nar- 

 roweft portion of the whole canal is juft where the bulb and 

 membranous part join. In the bulb it is again confiderably 

 enlarged, and after contrafting flightiy, preferves a cylin- 

 drical figure and uniform fize to the bafe of the glans. 

 There it again dilates, and forms what fome anatoraifls 

 have called the fofl'a navicularis ; its anterior opening is fome- 

 vvhat narrower, Mr. Home took the trouble of afcertain- 

 ing the dinienfions of the canal by filling it with wax, and 

 meafuring the call thus formed. The length was nine inches ; 

 from the external orifice to the bulb, fcven. The membra- 

 nous portion \.'as i\ inch, and the proftatic part of the canal 

 half an incli. The diameter of the raft, at ;- of an inch from 



nous fides of the urethra, lined by a continuation of the in- 

 ternal membrane of this canal, and about large enough to 

 admit a large hog's briftle. They are of various lengths, 

 but commoily about a quarter of an inch. Sometimes 

 fjveral fmaller join into one larger duCl. If carefully exa- 

 mined, their whole Jiumber will not be found Icfs than 60 or 

 70. No glandukr apparatus can be difcerned connedlcd 

 with them. In thefe tubes the mucous fluid is fecreted, by 

 v.-hich the furface of tlie urethra is fmeared, and defended 

 from the aftion cf the urine. Where thefe lacKux do not exift, 

 as in the bulb, membranous portion and proftate, a proteClin'j- 

 fluid is furnifhed from other lources, as Cowper's glands and 

 the proftate. The fluid of the lacunx feems to be a clear 

 vifcid fecretion, fimilar in appearance and tenacity to the 

 white of egg. In this form it can be exprelTed from the 

 openings on the furface of the urethra. Under various cir- 

 cumftances cf difeafe it is ir.creafed in quantity, and va- 

 riouHy altered from its natm'al properties, as in gonorrhoea 

 and gleet, and in ftrifturc. In fome of thefe inftances, it is 

 a clear, tranfparent, vifcid fluid, being the natural fecretion 

 in a more abundant form. 



The fides of the urethra are differently organized in dif- 

 ferent parts ; it is lined indeed throughout by a mucous 

 membrane, but this is covered externally by very different 

 ftruclurcs. Where the canal is pafTipg through the proftate, 

 the fides are formed merely by the mucous membrane, clofely 

 united to the gland by a dcnfe cellular texture. The finn 

 fubftance of the proftate, fo intimately connciSled with thff 

 canal, gives to it a ftrength and thickaefs in this part. The 

 membranous portion is differently circumftanced ; this is the 

 thinneft, and leaft firmly fuppoited divifion of tlie canal, 

 and, as it is placed in the bend of the urethra, is particularly 

 liable to injury in the employir-enl of the catheter. Even 

 liCre the membrane is covered by a denfe cellular texture, 

 continued from the proftate, and by tlie mufcular fibres 

 already dcfcribed. In the fpongy portion of the uretlira, 

 the fides of the canal are covered by a fubftance of peculiar 

 organization, analogous in its effects to that v.hii-'a fills the 

 corpora cavernofa penis. This is called corpus ipongiofum 



_the external orifice, was 9-20ths of an inch in a fubjeft of urethrx, or corpus cavernofum. It begins in- front of the 

 80 year.Sj and 7-2Cths in one of 30 years ; at 4 1 inches from membranous part of the canal, by a large protuberance 

 t'le external orifice 7-20ths ; at the bulb of the urethra already mentioned, as the bulb of the urethra. It form.s an 

 i2-20thj; in the membianous part, immediately adjoi.mng oblong rather elongated produclion, hanging between the 



crura 



