150 TOPOGRAPHIC AND APPLIED ANATOMY. 



tions are very favorable for an extension of the process internally along the urethra and an 

 involvement of the entire genito-urinary apparatus. 



The Rectum. The rectum lies behind the bladder and runs from the promontory to the 

 anus in a double curve. The first or long curve corresponds to the hollow of the sacrum, and 

 is known as the sacral curve (flexura sacralis). It extends to the tip of the coccyx and to the 

 prostate, and the concavity of the curve is directed anteriorly. The second or short curve is 

 in the perineum (flexura perinealis}; it is convex anteriorly, only about three centimeters in 

 length, and is surrounded by the external sphincter ani muscle. A knowledge of these curves 

 is important for operative procedures and for the introduction of the rectal speculum. The 

 rectum also deviates from the median line in some cases, but to so slight a degree that the 

 variation is of no practical importance. The narrowest portion of the rectum is its termination, 

 which is surrounded by the sphincters. Just above this is a dilatation, the ampulla recti, which 

 is particularly developed posteriorly. The posterior wall of the rectum is attached to the 

 sacrum by loose connective tissue in which are situated a number of lymphatic glands. These 

 glands extend upward to the sacroiliac articulation; in cases of rectal carcinoma they become 

 involved and must be removed. In this neighborhood there is also a large number of veins 

 which anastomose with the venous hemorrhoidal plexus surrounding the anus. The perineal 

 curve borders anteriorly upon the prostate gland. At this point rectal carcinoma may extend 

 to the prostate, the prostate may be treated surgically through the anterior rectal wall, and 

 prostatic hypertrophy and calculi situated in the fundus of the bladder may press upon the 

 rectum and render defecation difficult. 



The sacral curve may be subdivided into two sections. The inferior one is situated below 

 the recto vesical fold and is consequently not covered by peritoneum. It borders anteriorly 

 upon the fundus of the bladder, the ampullas of the vasa deferentia, and the seminal vesicles; 

 these parts may therefore be involved by the extension of a rectal carcinoma. In this situation 

 the bladder may be entered from the rectum without opening the peritoneal cavity. Only the 

 anterior surface of the lower end of the superior portion of the sacral curve is covered by peri- 

 toneum ; higher up the lateral surfaces are also covered, while at the promontory, the peritoneum 

 almost completely surrounds the rectum and fixes it to this point by a short mesorectum. In 

 operating high up in the rectum it must be remembered that the danger of opening the peritoneal 

 cavity increases as we ascend. The distance between the deepest point of the rectovesical fold 

 and the anus, measured along the anterior rectal wall, is about six to eight centimeters. The 

 situation in which the rectum possesses a lateral peritoneal reflection is from twelve to fourteen 

 centimeters above the anus. From the relation of the rectum to the sacrum it will be seen that 

 this portion of the intestine may also be attacked from behind after the resection of a portion 

 of the sacrum. 



THE PELVIC CAVITY IN THE FEMALE. 



The essential difference between the relations of the pelvic viscera in the two sexes is due 

 to the fact that the male genitalia take up less space and are situated almost entirely outside of 

 the pelvis. In the female, however, the ovaries, the tubes, the uterus, and the vagina are pushed 





