THE INGUINAL CANAL. 1023 



ligament, there joining with the fascia iliaca ; and on the inner side it blends 

 with the conjoined tendon of the internal oblique and transversalis muscles, 

 as well as with the tendon of the rectus. The fascia possesses very different 

 degrees of density in different cases ; in some being little more than a loose 

 areolar texture, while in others it is so resistant at the groin towards which 

 part it increases in thickness, and especially at the lower side of the 

 internal abdominal ring that it is calculated to afford material assistance 

 to the muscles in supporting the viscera. By an oval opening in this mem- 

 brane the spermatic cord, or the round ligament of the womb, begins its 

 course through the abdominal parietes. This opening, named the internal 

 abdominal ring, is opposite the middle of Poupart's ligament, and usually 

 close above that structure, but occasionally at a distance of three or four 

 lines from it. Its size varies a good deal in different persons, and is consi- 

 derably greater in the male than the female. From the edge of the ring 

 a thin funnel-shaped elongation (iufundibuliform fascia ; fascia spermatica 

 iuterna, Cooper), is continued over the vessels of the spermatic cord. 



Epigastric Artery. The position of this vessel is one of the most im- 

 portant points in the anatomy of the inguinal region, from the close 

 connection which it has with the different forms of inguinal hernia and with 

 the femoral hernia. Accompanied by two veins (in some instances by only 

 one) the vessel ascends under cover of the fascia last described obliquely to 

 the rectus muscle, behind which it then proceeds to its ultimate distribu- 

 tion (p. 432). In this course the artery runs along the inner side of the 

 internal abdominal ring close to the edge of the aperture or at a short 

 interval from it. The vessels of the spermatic cord are therefore near to 

 the epigastric artery ; and the vas deferens, in turning from the ring into 

 the pelvis, may be said to hook round it. 



The Inguinal Canal. This channel, by which the spermatic cord passes 

 through the abdominal muscles to the testis, begins at the internal abdo- 

 minal ring, and ends at the external one. It is oblique in its direction, 

 being parallel with and immediately above the inner half of Poupart's liga- 

 ment ; and it measures two inches in length. In front the canal is bounded 

 by the aponeurosis of the external oblique muscle in its whole length, and 

 at the outer end by the fleshy part of the internal oblique also ; behind it, 

 is the fascia transversalis, together with, towards the inner end, the con- 

 joined tendon of the two deeper abdominal muscles. Below, the canal is 

 supported by the broad surface of Poupart's ligament, which separates it 

 from the sheath on the large blood-vessels descending to the thigh, and from 

 the femoral canal at the inner side of those vessels. 



The spermatic cord, which occupies the inguinal canal, is composed of 

 the arteries, veins, lymphatics, nerves, and excretory duct (vas deferens) of 

 the testis, together with a quantity of loose areolar tissue mixed up with 

 those parts. The direction of the vessels just enumerated requires notice. 

 The artery and vein incline outwards from the lumbar part of the vertebral 

 column to roach the internal abdominal ring, where, after being joined by 

 the vas deferens as it emerges from the pelvis they change their course, 

 inclining inwards along the inguinal canal ; at the end of which they 

 become vertical. There are thus repeated alterations in the direction of 

 the vessels ; and while at the beginning and ending all are close to the 

 middle line of the body, they are considerably removed from that point 

 where they come together to emerge from the abdominal cavity. 



The coverings given from the constituent parts of the abdominal wall to 

 the spermatic cord and the testis, namely, the creiaasteric muscular fibres 



