924 



PERINEUM. 



sibility of rendering the urethra straight by 

 simple traction of the penis. 



The true suspensory ligament is calculated 

 by its position and strength to prevent the 

 surgeon from depressing the penis sufficiently 

 to straighten the urethra, and in the dead sub- 

 ject no force so applied, short of what suffices 

 to tear the ligament in question and to rupture 

 partially the attachment of the crura penis to 

 the bones, can efface the curvature of the pos- 

 terior segment of the canal, but if the suspen- 

 sory ligament be divided by the knife, and if 

 at the same time the crura penis be detached 

 ever so little from the pubis, the slightest trac- 

 tion exercised subsequently upon the penis 

 renders the urethra perfectly straight. The 

 writer by no means intends to deny that cathe- 

 terism by straight instruments is a feasible 

 operation : to straighten the urethra by drawing 

 the penis in certain directions, and without any 

 other aid, is one thing, and to introduce a 

 straight instrument into the bladder along the 

 urethra is a totally different matter; to accom- 

 plish the former, either in the living or the 

 dead subject, so long as the true suspensory 

 ligament is uninjured and the crura penis re- 

 tain their attachments, will be found absolutely 

 impossible, whilst the latter operation may 

 very generally be performed by any surgeon 

 who possesses ordinary dexterity. The princi- 

 ple on which the introduction of straight in- 

 struments is effected admits of ready explana- 

 tion. By raising the penis as before described 

 the operator renders the urethra, from the 

 glans to the bulb inclusive, perfectly straight, 

 and therefore the staff" traverses the passage 

 so far without impediment, but any attempt 

 to force it farther in the same direction would 

 rupture the lower wall of the urethra, and pro- 

 pel the point of the instrument towards the 

 rectum. The hinder portion of the canal leads 

 upwards and backwards to the bladder, and it 

 therefore remains to be explained how a straight 

 instrument, occupying the spongy part of the 

 urethra, and with its point directed downwards 

 and backwards towards the rectum, can have 

 its course so changed as to pass upwards and 

 backwards to the bladder. The solution of the 

 problem is easy : the handle of the instrument 

 is first drawn forwards so as to form a right 

 angle with the pubis, and then depressed until 

 it becomes nearly parallel with the patient's 

 thighs, whilst at the same time an onward 

 movement is communicated to it, whereby the 

 point glides upwards and backwards into the 

 bladder. In these movements the staff ob- 

 viously represents a lever of the first order, the 

 fulcrum formed by the lower wall of the ure- 

 thra opposite to the true suspensory ligament of 

 the penis, and the beak of the instrument 

 being elevated as its handle is depressed. 



In addition to its curvature, that part of 

 the urethra which belongs to the perineum pre- 

 sents other features of interest to the surgical 

 anatomist. In the dead subject its diameter is 

 naturally far from uniform, whilst in the living 

 its calibre is exceedingly liable to vary, accord- 

 ing to the contraction or relaxation of the 



muscular expansions which in certain situations 

 invest it. Its parietes also exhibit in many 

 places peculiarities of organisation calculated 

 to embarrass the surgeon, and therefore some 

 further notice of this part of the canal becomes 

 here necessary. 



The prostatic portion of the urethra is an 

 inch and a quarter or at most an inch and a half 

 in length. In the adult it takes an oblique 

 direction from above and behind downwards 

 and forwards ; but in the aged subject it runs 

 more horizontally, a change produced by the 

 developement of the " bas fond" of the bladder ; 

 and in the child its course is nearly vertical in 

 consequence of the position of the bladder at that 

 period of life. The piostatic urethra is slightly 

 contracted at each extremity, whilst in the in- 

 termediate space it is somewhat widened, the 

 dilatation being most observable near its lower 

 wall. The veruraontanum or caput gallina- 

 ginis, a prominent fold of mucous membrane, 

 extends in the middle line along the floor of 

 this part of the canal : it exhibits anteriorly a 

 depression named the sinus pocularis, the orifice 

 of which is directed forwards, whilst on either 

 side the aperture of the common ejaculatory 

 duct usually opens. The verumontanum is 

 placed between two deep depressions called 

 the prostatic sinuses ; these contain numerous 

 orifices of the prostatic ducts, a few only being 

 observable on the upper wall of the urethra. 

 At the posterior extremity of each sinus a 

 transverse fold of mucous membrane, of which 

 the free concave margin looks forwards, may 

 be occasionally observed ; this has been called 

 the " pyloric: valve " by M. Amussat ; but in 

 the majority of subjects no such structure exists, 

 and when present it is generally occasioned by 

 an incipient enlargement of the third lobe of 

 the prostate gland, which, projecting upwards 

 from below, elevates the mucous membrane 

 at either side, so as to produce the valvular 

 arrangement in question. 



From this brief exposition it follows that 

 many impediments to catheterism may be en- 

 countered in the prostatic portion of the urethra. 

 The ducts which open upon its walls having 

 their orifices mostly directed forwards, are 

 sometimes morbidly enlarged, when they might 

 easily arrest the point of a fine bougie; whilst 

 the prostatic sinuses forming depressions below 

 the level of the floor of the urethra and the 

 folds of mucous membrane just described, are 

 also calculated at times to entangle a small- 

 sized instrument. Most of these impediments 

 are situated along the floor of the urethra, and 

 from their very nature they are likely to obstruct 

 none but the smallest instruments. To avoid 

 them, therefore, the surgeon should if possible 

 select an instrument of large size and direct 

 the point along the upper wall of the passage. 

 The difficulties of catheterism are sometimes 

 vastly increased by disease of the prostate gland, 

 but obstructions of that description are beyond 

 the scope of this article. The remarkable 

 sympathy so constantly observed in practice 

 between the testicle and the urethra is explained 

 by the manner in which the lining membrane 



