118 



ANATOMY AND PHYSIOLOGY OF 



from the cervix forward toward the body, 

 where the fibres diverge and become oblique, 

 and some even circular ; this layer is prin- 

 cipally developed posteriorly. The inner or 

 circular layer is not arranged in concentric 

 rings ; but its fibres, beginning at- the fund- 

 us, appear to arise from various centres on 

 the surface, and to be taking a direction 

 more or less curved in difleront parts, so as 

 to get transversely to the long axis of the 

 viscus, and thus from the inner side have a 

 circular appearance. These fibres arc more 

 decidedly circular at the neck, and act some- 

 what like a sphincter. Some of the deeper 

 fibres at the neck of the bladder extend for- 

 ward to each orifice of the ureter, marking 

 the limit of the vesical trigon, whose office 

 must be that of approaching the lips of the 

 elliptical apertures. 



The mucus coat of the bladder is gener- 

 ally more or less coated with mucus and 

 epithelium, which guard the structm*e from 

 the corroding effects of the secretion it has to 

 come in contact with. It is thrown into 

 numerous folds, taking various directions, 

 but principally concentrical toward the 

 fundus, and longitudinal at the cervix, all 

 of which are effaceable by distention of the 

 bladder, and are most prominent when the 

 latter is collapsed. At the upper part of 

 the urethral orifice of the bladder the mucus 

 lining is smooth and free from folds, mark- 

 ing out a triangular space, bounded ante- 

 riorly by a line drawn between the orifices 

 of the ureters, and laterally by two lines 

 meeting at a spot at the superior part of 

 the vesical orifice. This is termed the 

 vesical trigon. At its apex is a projecting 

 fold of mucus membrane or uvula vesicae, 

 which seems to moderate the flow of urine 

 into the urethra. 



The bladder is supplied with blood from 

 the internal pudic, and its veins empty into 

 the internal pudic vein. 



The nerves of the bladder are derived 

 from the sympathetic, and partly from the 

 two last sacral pairs which supply the neck. 



The lymphatics go to glands surrounding 

 the origin of the ifiac arteries, termed pelvic 

 lymphatic glands, from which vessels arise, 



communicating anteriorly with the recepta- 

 culum chyli. 



URETHRA. 



This canal in the male subject is not only 

 purposed for the passage of urine, but also 

 transmits the products of the generative or- 

 gans. It extends from the posterior part of 

 the bladder to the glans penis ; but we shall 

 only occupy ourselves with a description of 

 the intra-abdominal or pelvic portion, which 

 terminates at the bulb of the penis or ischial 

 arch. 



It is continuous anteriorly with the blad- 

 der, attached to the rectum arid sides of the 

 pelvis by fascia and loose cellular tissue 

 and muscles. 



The urethra is cylindrical, of considerable 

 length, and its coats of no mean thickness. 

 The pelvic portion of the vu-ethra is gener- 

 ally about three or four inches long, taking 

 a direction backward and somewhat up- 

 ward. 



It is related superiorly to the vesiculee 

 seminales, middle lobe of the prostate, and 

 posteriorly it comes in contact with the rec- 

 tum, but separated from it laterally by 

 Cowper's glands. 



The first or prostatic portion of the ure- 

 thra is purely membranous, strengthened by 

 cellular tissue and a continuation of the 

 fibres of the bladder, the circular ones in 

 particular, which are abundant anteriorly. 

 The posterior two-thirds of the pelvic por- 

 tion of the urethra are covered by a thick 

 red muscular layer, which completely encir- 

 cles it, with the exception of that part 

 coming in contact with Cowper's glands. 

 This muscle is continuous behind wdth the 

 muscular fibres of the penis, which consti- 

 tute the accelerator urinae. These fibres 

 are externally mixed with longitudinal ones, 

 a portion of which are merely the inner or 

 inferior bundles of the retractor ani, whilst 

 others are derived from the triangularis 

 penis ; both of these muscles tend to fix the 

 urethra. Postero-superiorly the fibres en- 

 cii'cling the urethra are blended with the 

 external anal sphincter. The retractor penis, 

 which gets attached to the sacral bone, is a 



