THE SCROTUM. 1961 



ring, is most distinct above, becoming thinner as it descends, until over the testicle it 

 loses its identity as a distinct investment. 



The coverings of the spermatic cord receive their blood-supply from chiefly the 

 cremasteric branch of the deep epigastric artery ; additional cremasteric twigs from 

 the spermatic artery are distributed to the upper part of the cord, anastomosing with 

 those from the first-named source. The nerves include the genital branch of the 

 genito-crural and usually a twig along the front of the cord from the terminal branch 

 of the ilio-inguinal. 



4. The riidime7itary strucUires, the remains of the processus vaginalis, the para- 

 didymis, and sometimes the vas aberrans. After closure of the communication between 

 the serous pouch and the peritoneal cavity, the processus vaginalis is represented by 

 a delicate fibrous band (ligamentura vaginale) that maybe traced, under favorable con- 

 ditions, from the internal abdominal ring above through the spermatic cord a^ far as 

 the upper margin of the tunica vaginalis below. The paradidymis (page 1950) lies 

 within the lower end of the spermatic cord, immediately above the epididymis, or 

 behind its upper pole, and in front of the venous plexus. Occasionally, when unusu- 

 ally developed, the vas aberrans (page 1950) may also extend into the lower end of 

 the spermatic cord. 



In addition to the foregoing cov^erings proper, the spermatic cord is enveloped 

 by the skin, the superficial and the deep layer of the superficial fascia. The deep 

 layer olf the latter is important, being continuous above with the fascia on the abdomen 

 and belpw, after investing the testicle, with CoUes's fascia in the perineum. 



PRACTICAL CONSIDERATIONS : THE SPERMATIC CORD. 



The most frequent pathological condition associated with the cord (and not else- 

 where described) is varicocele, an enlargement — with dilatation and lengthening — of 

 the veins of the cord, occurring most frequently in young unmarried adults (fifteenth 

 to twenty-fifth year) and on the left side (90 per cent, of cases). 



The veins composing the spermatic plexus can be ranged in three groups, the 

 most anterior of which has in its midst the spermatic artery, the middle the vas def- 

 erens, and the posterior is composed of those veins which pass upward from the tail 

 of the epididymis. The anterior group is the one first affected, or. if the dilatation 

 affects all the veins, is most extensively .involved. 



It is thought that varicocele often depends upon a congenital predisposition, 

 but many anatomical reasons have been given to account (a) for its occurrence, and 

 i^b) for its greater frequency on the left side. (a) i. The relative length and the 

 vertical course of the veins. 2. The lax tissue surrounding them, so that (as with 

 the long saphenous vein) they derive little support and their blood-current receives 

 no aid from the presence or contraction of surrounding muscles. 3. Their large size 

 as compared with the corresponding artery, so that the vis a tergo must be reduced to 

 a minimum (Treves). 4. Their tortuosity, frequent anastomosis, and few and imper- 

 fect valves. 5. The pressure exerted upon them as they pass through the inguinal 

 canal, not altogether unlike that experienced by the hemorrhoidal veins in their passage 

 through the walls of the rectum, {b') i. The veins in the left cord are much larger 

 than those in the right. 2. The left testicle hangs lower than the right, so that the 

 column of blood in the left veins is longer. 3. The left spermatic vein empties into 

 the left renal vein at a right angle, whereas the right spermatic vein empties into the 

 vena cava at an acute angle. 4. The left spermatic vein running behind the sigmoid 

 flexure of the colon is constantly subjected to pressure from accumulation of faeces in 

 the bowel. 



In the operation for varicocele by excision of the pampiniform plexus the sper- 

 matic artery is often included, but gangrene of the testicle does not follow because 

 of the escape of the deferential artery and of its free anastomosis with the spermatic 

 and scrotal vessels. 



THE SCROTUM. 



The scrotum, the more or less pendulous sac of integument that contains the 

 testicles and the associated structures and the lower part of the spermatic cords, is 

 attached to the under surface of the penis in front and to the perineum behind. Flat- 



