400 



DISSECTION OF THE PELVIS. 



pudic, 



dorsal vein 

 of penis, 



haemor- 

 rhoidal, 



vesical, 

 uterine, and 



vaginal 

 veins. 



Other 

 arteries in 

 the pelvis. 



Ovarian 

 artery : 

 offsets. 



Superior 



hfemor- 



rhoidal 



ends in 

 loops. 



Middle 

 sacral, 

 which has 



lateral 

 offsets. 



Dissection 

 of the nerves 

 of the pelvis 



The pudic veins receive roots corresponding with the branches of 

 the pudic artery in the perineum, but not those corresponding 

 with the offsets of the artery on the dorsum of the penis. 



The dorsal vein of the penis receives veins from the corpora 

 cavernosa and corpus spongiosum of the penis, and entering the 

 pelvis below the symphysis pubis, divides into two, a right and 

 a left branch, which join a large plexus round the prostate (prostatic 

 plexus). 



The middle hcemorrhoidal vein communicates with a large plexus 

 (haemorrhoidal) around the lower end of the rectum beneath the 

 mucous membrane. 



The vesical veins begin in a plexus about the fundus of the 

 bladder, and anastomose with the prostatic and hcemorrhoidal veins. 



The uterine veins are numerous, and form a plexus in and by the 

 side of the uterus : this plexus inosculates above with the ovarian 

 plexus, and below with one on the vagina. 



The vaginal veins surround their tube with a large vascular 

 plexus communicating with the veins of the bulb of the vestibule 

 below and with the uterine plexus above. 



The arteries in the pelvis, which are not derived from the 

 internal iliac, are the ovarian, superior hsemorrhoidal, and middle 

 sacral. 



The OVARIAN ARTERY (p. 365), after passing the brim of the 

 pelvis in the ovario-pelvic ligament, becomes tortuous, and enters 

 the broad ligament to be distributed to the ovary : it supplies an 

 offset to the Fallopian tube, and another to the round ligament ; 

 and a large branch anastomoses internally with the uterine artery. 



The SUPERIOR H^MORRHOIDAL ARTERY, the continuation behind 

 the rectum of the inferior mesenteric (p. 318), divides into two 

 branches near the middle of the sacrum. From the point of division 

 the branches are continued along the rectum, one 011 each side, and 

 each ends in about three branches, which pierce the muscular layer 

 of the gut three inches from the anus ; they terminate opposite the 

 internal sphincter in anastomotic loops beneath the mucous mem- 

 brane, and anastomose with the middle and inferior hsemorrhoidal 

 arteries. 



The MIDDLE SACRAL ARTERY arises from the back of the aorta 

 just before its bifurcation (fig. 148, 6) and descends along the middle 

 of the last lumbar vertebra, the sacrum, and the coccyx. The 

 artery gives small branches laterally, opposite each piece of the 

 sacrum, to anastomose with the lateral sacral arteries, and to supply 

 the nerves, and the bones with the periosteum. Sometimes a 

 small branch is furnished by it to the lower end of the rectum, 

 to take the place of the middle heemorrhoidal artery. 



The middle sacral veins end in the left common iliac. 



Dissection (fig. 149, p. 401). To dissect the nerves of the 

 pelvis, on the right side, it will be necessary to detach the 

 triangular ligament with the urethra from the bone ; and to cut 

 through, on the right side, the fore part of the recto- vesical fascia 

 and levator ani, together with the visceral arteries, in order that 



