THE PELVIC CAVITY IN THE MALE. 147 



cavernosus muscle arises from a tendinous raphe' commencing at the anus; its fibers diverge 

 anteriorly, surround the bulb of the urethra, and run to the corpora cavernosa of the penis. 

 The constrictor cunni muscle radiates anteriorly from the anus, covers the bulbi vestibuli, sur- 

 rounds the entrance of the vagina, and runs over the dorsum of the clitoris. The ischiocavernosus 

 muscle arises from the anterior margin of the ascending ramus of the ischium, covers the corpus 

 cavernosum penis (or clitoridis), and radiates to the lateral and dorsal surfaces of the penis (or 

 clitoris). The superficial transversus perinei muscle varies greatly in different individuals; it 

 runs from the descending ramus of the ischium to the median line, where it becomes continuous 

 with its fellow of the opposite side and with the bulbocavernosus muscle. 



It should be clearly understood that chronic inflammations in the posterior pelvic wall, 

 particularly those in the region of the sacroiliac articulation, may extend posteriorly to the sacral 

 and the lumbar regions, anteriorly to the pelvic space, from which they may pass inward to the 

 rectum, to the bladder, or to the uterus, downward through the pelvic diaphragm to the ischio- 

 rectal fossa, or posteriorly through the sacrosciatic foramina beneath the gluteal muscles. Sup- 

 purations originating in the pelvic viscera (for example, in the prostate, in the seminal vesicles, 

 and in that portion of the urethra situated above the urogenital diaphragm) may pass downward 

 through the diaphragm, reach the ischiorectal fossa, and then perforate the skin near the anus. 

 The so-called periproctitic abscesses, originating independently in the fat of the ischiorectal 

 space, may also point in the same situation, and, under certain circumstances, such abscesses 

 may be felt as swellings through the rectal wall by the finger introduced into the anus. 



The vessels and nerves of the pelvic space should be recalled to memory by the aid of a text- 

 book of systematic anatomy. The branches of the internal iliac artery in the male and in the 

 female, and the lumbar and sacral plexuses with their respective branches, should also be re- 

 viewed. 



THE PELVIC CAVITY IN THE MALE. 



The Urinary Bladder. The male urinary bladder (Plate 21), when distended, takes 

 up the greater portion of the pelvic cavity. It is in relation with the anterior pelvic wall. Its 

 position varies with the state of distention, since the full bladder extends particularly upward 

 and backward, although it also enlarges laterally. When empty, it barely extends above the 

 upper margin of the symphysis; while when extremely distended, it may reach almost to the 

 navel, compressing and displacing the small intestines situated posterior to the viscus. It con- 

 sequently follows that when it is desired to enter the bladder above the symphysis, by puncture, 

 for example, the rule is to previously distend the bladder artificially to avoid the danger of 

 entering the peritoneal cavity (see page 127). By this route, calculi and tumors may be removed 

 from the bladder and the urethra may be catheterized (catheterismus posterior) (retrograde 

 catheterization). The internal orifice of the urethra is situated in the median line about three 

 centimeters behind the middle of the symphysis. [According to Cunningham, the posterior 

 opening of the urethra is slightly below the level of and from 2 to 2$ inches behind the upper 

 border of the symphysis. It is easily reached through a suprapubic wound. ED.] The inferior 

 wall of the bladder rests upon the prostate gland. The anterior surface is connected to the 

 pelvic wall by loose connective tissue which allows the distended bladder to ascend into the 



