PELVIS 603 



systems of veins. This is of practical importance in associa- 

 tion with the production of haemorrhoids or piles, which are 

 due to a varicose condition of the haemorrhoidal veins. It 

 has been noted that the portal vein and its tributaries are 

 without valves ; consequently, anything which retards the flow 

 of blood through the portal system will react upon the 

 haemorrhoidal plexus, cause its distension, and predispose to 

 haemorrhoids. 



Vena Hypogastrica (O.T. Internal Iliac Vein). This 

 is a trunk which lies behind the hypogastric artery. Its 

 tributaries correspond to the branches of the hypogastric 

 artery, except that the ilio-lumbar vein opens into the 

 common iliac vein. 



The Lymph Vessels of the Pelvis. It is only in rare cir- 

 cumstances that the dissector will be able to display any of the 

 pelvic lymphatic vessels, but in favourable subjects he will be 

 able to localise some of the pelvic lymph glands. The main 

 groups of lymph glands of the pelvis are (i) the hypogastric 

 glands ; (2) the sacral glands ; and (3) the rectal glands. The 

 hypogastric glands are situated on the lateral pelvic wall, 

 near the origins of the branches of the hypogastric artery. 

 They receive lymphatics from the membranous part of the 

 urethra, the lower part of the bladder, the prostate, the 

 upper part of the anal canal, and the lower part of the 

 rectum. Their efferent vessels pass to glands situated 

 round the common iliac artery. The sacral glands lie along 

 the medial sides of the anterior sacral foramina. They 

 receive lymph vessels from the adjacent bones and ligaments, 

 from the rectal glands, and from the prostate. Their efferent 

 vessels end in the common iliac glands. The rectal glands, 

 four or five in number, lie in relation with the superior 

 haemorrhoidal vein and its two main tributaries. They 

 receive lymph from the rectum, and their efferent vessels 

 terminate in the lateral sacral glands. 



Dissection. As soon as the examination of the pelvic vessels is com- 

 pleted the viscera should be drawn as far as possible from the lateral wall 

 of the pelvis, any vessels which tend to prevent the movement should be 

 divided, and then the pelvic diaphragm should be examined. It is com- 

 posed of two muscles on each side viz. the levator ani and the coccygeus. 

 Both the muscles must be cleaned, and whilst this is being done care must 

 be taken to avoid injuring the fifth sacral and the coccygeal nerves as they 

 pierce the coccygeus near the coccyx. 



M. Levator Ani. This is a strong sheet of muscle fibres, 



