924 ^ MANUAL OF ANATOMY 



rectum are now to be more fully examined, after which the gut is to be separated 

 from the other structures, and subjected to a special dissection. The superior 

 hemorrhoidal artery is to be followed out in two divisions, laterally disposed. 

 The tow having been removed, and one end securely tied, the gut is to be in- 

 flated from the other end, which is then to be ligatured. The arrangement of 

 the longitudinal and circular muscular fibres are to be shown, and the thicken- 

 ing of the latter along the anal canal, which gives rise to the internal 

 sphincter, is to be noted. The gut is now to be laid open from end to end, 

 and its interior examined. The valves of Houston, three in number, are to 

 be looked for as transverse crescentic folds. One will be found on the right 

 side fully 3 inches above the anus, and two on the left side about i inch 

 above and below the right valve. The part of the bowel surrounded by the 

 internal sphincter muscle is to be studied as the anal canal. The longitudinal 

 folds seen here, called the columns of Morgagni, are to be examined, and a 

 little above the anus these columns will be seen to be connected by circularly- 

 disposed semilunar folds, known as the anal valves. The entire blood-supply 

 of the rectum should be carefully revised. 



The bladder is next to be dissected, showing the ureters at the lateral angles, 

 and the vesiculae seminales and vasa deferentia at the fundus. The commence- 

 ment of each common ejaculatory duct is also to be shown, this being formed 

 by the union of a vesicula seminalis and vas deferens. The limited area on 

 the fundus, bounded on either side by these structures, and called the external 

 trigone, is to be studied. The peritoneum having been removed from the 

 upper surface of .the bladder, the muscular fibres of the viscus are to be 

 displayed as well as possible. They will be found to be arranged as an external 

 longitudinal, a middle circular, and an internal longitudinal, layer, the last 

 being very indefinite. The fibrous cord, representing the urachus, is "to be 

 shown passing from the apex of the bladder. The prostate gland is now to 

 be fully examined, and, if not previously dissected, its recto-vesical capsule 

 and the prostatic venous plexus are to be shown. At the base of the gland 

 the dissector should look for the middle lobe, which is represented by the small 

 part lying between the common ejaculatory ducts and the wall of the bladder, 

 the rest of the organ being disposed as two lateral lobes. The membranous 

 part of the urethra is to be shown succeeding to the apex of the prostate gland. 

 A vesicula seminalis may now be cut into, in order to show the reticulated 

 arrangement of its mucous lining. The bladder is to be opened, and its interior 

 carefully examined. The openings of the ureters and the urethral opening 

 are to be noted, and the smooth internal trigone examined, which lies within 

 ridges connecting these openings. The prostate gland is also to be laid open 

 along its anterior surface, and the whole penis is to be laid open, so as to 

 expose the interior of the corpora cavernosa, and the urethra contained in the 

 corpus spongiosum. In the prostatic urethra the central dilatation and the 

 constriction at either end are to be observed, as well as the following mark- 

 ings : the crest, along the posterior wall ; the sinus pocularis, having on the 

 lateral margins of its opening, or just within them, the openings of the common 

 ejaculatory ducts ; and the prostatic sinus, on either side of the crest, in which 

 the prostatic ducts open. The spongy urethra is next to be examined, and 

 the dilatation towards its centre, and also in the glans, are to be observed, 

 the latter being called the fossa navicularis. The openings of the glands of 

 Littre and the lacunae of Morgagni are to be noted. The septum pectini- 

 forme of the corpora cavernosa, and their trabecular tissue, which supports 

 the erectile tissue, are to be observed. 



In the female the bladder is to be examined as in the male. The absence of a 

 prostate gland is to be noted, and the urethra is to be laid open, its short- 

 ness and distensibility being observed. The vagina is to be opened from 

 end to end by an incision along the lateral wall. Its mucous rugae are to 

 be examined, as well as the carunculae myrtiformes at its external orifice, 

 and the lower part of the cervix uteri, which is received into its anterior wall 

 at the upper end. The transverse slit of the os uteri externum is to be 

 studied, along with its anterior and posterior lips. The recesses formed by the 

 vagina around the lower part of the cervix uteri, called the fornices, are to be 



