SUPERFICIAL VEINS OF UPPER EXTREMITY 639 



triangular ligament. Before passing through the trianguhir ligament, it connnuiii- 

 cates on each side witli the ]>rimarv radicals of the pudic vein. After dividing ii;t<i 

 a right and a left hrancli within the pelvis, each vessel generally communicates witli 

 the ol^turator vein by a branch passing over the ))ack of the pubes to the ol»turati>f 

 foramen. 



The prostatico-vesical plexus surrounds the prostate and the neck and lowir 

 fundus of the bladder. It receives in front the right and left divisions of the 

 dorsal vein of the penis, and communicates i)Osteriorly with the ha-morrhoidal 

 ])lexus. The prostatic veins and the vesical plexus open into it. The veins 

 forming the plexus are of large size, especially in old men, in whom they oftt n 

 become varicose, and contain phlel)oliths, or vein-stones. The jdexus is surroundeil 

 by a kind of ca])sule formed by the i-ecto-vesical process of the pelvic fascia. It 

 terminates in a single stem on each side which opens into the internal iliac vein. 



The vesical plexus surrounds the upper fundus, the sides, and the anterior and 

 posterior surfaces of the Idadder. It is situated between the muscular coat and the 

 peritoneum, and where the bladder is uncovered by peritoneum external to the 

 nuiscular coat in the pelvic cellular tissue. It opens into the jirostatico-vesical 

 plexus. 



The haemorrhoidal plexus of veins surrounds the rectum, and is situated at 

 the lower part of that tul)e between the muscular and mucous coats. The veins of 

 this ])lexus terminate in the inferior, middle, and superior haemorrhoidal veins. 

 The inferior join the pudic; the middle accompany tlie middle hannorrhoidal 

 arteries, and open into tlie internal iliac and su])erior ha?morrhoidal veins; the 

 superior form the commencement of the inferior mesenteric vein, and through this 

 the l)lood gains the portal vein. None of these veins have any valves, hence the 

 enlargement of the inferior haemorrhoidal veins, a condition known as piles, when 

 the i)ortal vein is obstructed, as from compression of its ca}nllaries in cirrhosis of 

 the liver. Through the ha?morrhoidal veins a free communication is established 

 between the systemic and portal system of veins. 



5. TFFE VEINS OF THE UPPER EXTREmTY 



The veins of the upper limb consist of two sets — a superficial and a deep. 

 The sui)erficial veins ramify in the subcutaneous tissue al)ove the dee]) fascia; the 

 deep accompany the arteries, and have practically the same relations as those 

 vessels. The superficial and deep veins commimicate at frequent intervals tln-oi;gh 

 the internuiscular veins which run l)etween the muscles and perforate the deep 

 fascia. Both sets of veins are provided ^vith valves, Init the valves are more 

 numerous in the deep than in the superficial. Tliere is usually a valve where the 

 deep veins join the su])erficial. The superficial veins are larger than the deej^. and 

 take the greater sliarc in retin-ninif the blood. 



I. THE SUPER Fir lAL VEIXS OF THE UPPER EXTREMITY 



The superficial veins begin in two irreguhir venous plexuses: one situated on 

 the back oi the hand, and the other on the front of the wrist. From the radial 

 side of the dorsal plexus, a single vein, the superficial radial, runs u]) the forearm 

 as far as the ell)ow. From the ulnar side of the plexus, two veins course up the 

 inner side of the forearm — the anterior and posterior superficial ulnar veins — 

 and, joining together a little l)elow the ))end of tiie elbow, form a single superficial 

 ulnar vein. From tlie anterior ]»lexns a vein runs up the middle of the tront of 

 the forearm — the superficial median vein — and. after receiving a branch from the 

 deep veins at the bend of the elbow (tlic deep median), divides into an outer 



