1928 HUMAN ANATOMY. 



Epispadias is an absence of the upper wall of the urethra, is much rarer than 

 hypospadias, and is often associated with exstrophy of the bladder (page 191 1). It 

 may be extensive, in which case the opening of the urethra is close to the pubes, or 

 there may be congenital absence of the pubic symphysis. 



In relation to its injuries and diseases and to its use as the route by which instru- 

 ments are introduced into the bladder, the urethra may be divided into various por- 

 tions, as (a) anterior 2,n^ posterior ; {b) Jixed-dnd movable ; (c) curved a^nd straight ; 

 {a) ?iarro2v and wide; {e ) dilatable and non-dilatable; i^f) erectile and muscular ; 

 {g) pe?iile, perineal, and prostatic. 



{a) The anterior urethra includes all the spongy portion and the posterior or 

 deep urethra all the prostatic portion. They are separated, especially as regards 

 infectious processes, by the intervening membranous urethra, — that portion lying 

 between the two layers of the triangular ligament and surrounded by the compressor 

 urethrae muscle. The contraction of that muscle, acting on the narrowed urethra 

 of this region, constitutes a natural barrier to the backward progress of infection, 

 and is doubtless aided in this by the resistance to tumefaction offered by the un- 

 yielding inferior layer of the triangular ligament (the arbitrary boundary of the 

 "anterior" urethra posteriorly), and possibly, in the ordinary position of the male 

 organ, by gravity, as the movable prepubic downward curve of the urethra {^vide 

 infra) begins only a little anterior to that point. The division is a practical one, 

 and in its relation to the most common urethral infection (gonorrhceaj affects both 

 prognosis and treatment (page 1931). 



{b) The Jixed portion of the urethra includes the prostatic and the membranous 

 portions and a little — from one to one and a half inches — of the posterior part of 

 the spiongy portion. It may be said to extend from the neck of the bladder to the 

 posterior margin of the suspensory ligament of the penis, about two and a half inches 

 anterior to the inferior layer of the triangular ligament. Of this relatively fixed portion 

 the membranous urethra is the only part that has practically no mobility. The pros- 

 tatic portion may be moved slightly within the limits allow-ed by the pubo-prostatic 

 ligaments and by the connection of its capsule with the superior layer of the triangular 

 ligament in front and the recto-vesical fascia and rectum beneath and above. The 

 posterior part of the spongy urethra, the "bulbous" portion, has even more motion 

 both laterally and inferiorly, as its movement in those directions is not opposed by 

 any strong membranous or ligamentous structure. Of course, anterior to the suspen- 

 sory ligament the spongy urethra moves with the corresponding portion of the penis. 



This division, like the one following, is of great practical importance in urethral 

 or vesical instrumentation.  



(f) The terms curved and straight, as applied to the urethra, are purely rela- 

 tive. With the penis flaccid and pendent there is almost no straight portion, and the 

 urethra presents a reversed, irregular, S-shaped curve, the ujiper segment of which 

 begins a little anterior to the vesical orifice and is nearly vertical, with its concavity 

 forward in the erect position of the subject, while the lower and longer segment is 

 less vertical, is convex anteriorly, and ends at the meatus. The whole urethra may 

 be divided, as to its curves, into ( i ) a comparatively fixed stibpnbic curve, including 

 most of the prostatic urethra, all of the membranous urethra, and that portion of the 

 spongy urethra posterior to the suspensory ligament ; and (2) a prepubic curve, 

 including the remainder. The former, or fixed, curve is, for convenience, described 

 as that part of a circle of three and one-quarter inches diameter which is subtended by 

 a cord two and three-quarters inches long. Practically it varies greatly from this stand- 

 ard. It maybe flattened out by downward pressure (the patient being supine) with 

 a finger on each side of the root of the penis, thus elongating somewhat the slightly 

 elastic suspensory ligament and depressing the anterior limb of the curve ; it can 

 temporarily be obliterated, as in passing through it a straight instrument or the 

 straight shaft of an instrument with a terminal curve. The two ends of the curve 

 are approximately on the level of a line drawn through the under surface of the 

 symphysis at right angles to its vertical axis. The summit of the curve — the lowest 

 point with the subject erect — is on a line prolonging the vertical axis of the sym- 

 physis, and is at the centre of the membranous urethra and about an inch behind 

 and below the subpubic ligament. 



