THE RECTUM. 



377 



rectum, extends from the sigmoid flexure of the colon to the anus, and 

 is situated entirely within the true pelvis, in its back part (fig. 272, r, r). 

 Commencing opposite the left, sacro-iliac articulation, it is directed 

 at first obliquely downwards, and from left to right, to gain the middle 

 line of the sacrum. It then changes its direction, and curves forwards 

 in front of the lower part of the sacrum and the coccyx, and behind 

 the bladder, vesiculte seminales and prostate in the male, and at the 

 back of the cervix uteri and vagina in the female. Opposite the 



Fis. 272. 



Fig. 272. — Vertical Section op the Pelvis and its Viscera in the Male 

 (from Houston). ^ 



This figure is introduced to illustrate tlie form, position, and relations of the rectum ; 

 it also shows the bladder and urethra with the pelvic inflection of the peritoneum over 

 these viscera : r, r, r, the upper and middle parts of the rectum, and at the middle 

 letter the fold separating the two ; r, a, the lower or anal portion ; r, the upper part of 

 the urinary bladder ; v', the base, at the place where it rests more immediately on the 

 rectuta ; p, the prostate gland and prostatic portion of the urethra ; b, the bulb ; c, r, 

 the corpus cavernosum penis and suspensory ligament ; sc, the scrotum ; s, symphysis 

 pubis. 



prostate it makes another turn, and inclines downwards and backwards 

 to reach the anus. The intcstinum rectum, therefore, so called from its 

 original description being derived from animals, is far from being 

 straight in the human subject. Seen from the ft-ont, the upper part 

 of the rectum presents a lateral inclination from the left to the median 

 line of the pelvis, sometimes passing beyond the middle to the right; 

 and when viewed from the side (fig. 272), it offers two curves, one 

 corresponding with the hollow front of the sacrum and coccyx, and 



