DEEP CRURAL ARCH. 835 



a"bdomen, the transversalis fascia passing down in front of the femoral vessels, 

 and the iliac fascia descending behind them ; these fascia are directly contin- 

 uous on the iliac side of the femoral artery, but a small space exists between 

 the femoral vein and the point where they are continuous on the pubic side of 

 that vessel which constitutes the femoral or crural canal. The femoral sheath 

 is closely adherent to the contained vessels about an inch below the saphenous 

 opening, becoming blended with the areolar sheath of the vessels, but opposite 

 Poupart's ligament it is much larger than is required to contain them ; hence 

 the funnel-shaped form which it presents. The outer border of the sheath is 

 perforated by the genito-crural nerve. Its inner border is pierced by the in- 

 ternal saphenous vein, and numerous lymphatic vessels. In front, it is covered 

 by the iliac portion of the fascia lata ; and behind it is the pubic portion of the 

 same fascia. 



Deep Crural Arch. Passing across the front of the- crural sheath, and closely 

 connected with it, is a thickened band of fibres, called the deep crural arch. It 

 is apparently a thickening of the fascia transversalis, joining externally to the 

 centre of Poupart's ligament, and arching across the front of the crural sheath, 

 to be inserted by a broad attachment into the pectineal line, behind the conjoined 

 tendon. In some subjects, this structure is not very prominently marked, and 

 not unfrequently it is altogether wanting. 



If the anterior wall of the sheath is removed, the femoral artery and vein are 

 seen lying side by side, a thin septum separating the two vessels, and another 

 septum separates the vein from the inner wall of the sheath. The septa are 

 stretched between the anterior and posterior walls of the sheath, so that each 

 vessel is inclosed in a separate compartment. The interval left between the 

 vein and the inner wall of the sheath is not filled up by any structure, except- 

 ing a little loose areolar tissue, a few lymphatic vessels, and occasionally a 

 lymphatic gland ; this is the femoral or crural canal, through which a portion 

 of intestine descends in femo'ral hernia. 



The crural canal is the narrow interval between the femoral vein and the in- 

 ner wall of the crural sheath. It exists as a distinct canal only when the sheath 

 has been separated from the vein by d'issection, or by the pressure of a hernia 

 or tumor. Its length is from a quarter to half an inch, and it extends from 

 Gimbernat's ligament to the upper part of the saphenous opening. 



Its anterior wall is very narrow, and formed by the fascia transversalis, Pou- 

 part's ligament, and the falciform process of the fascia lata. 



Its posterior wall is formed by the iliac fascia and the pubic portion of the 

 fascia lata. 



Its outer wall is formed by the fibrous septum covering the inner side of the 

 femoral vein. 



Its inner wall is formed by the junction of the transversalis and iliac fascia3, 

 which forms the inner side of the femoral sheath, and covers the outer edge of 

 Gimbernat's ligament. 



This sanal has two orifices : a lower one, the saphenous opening, closed by the 

 cribriform fascia; an upper one, the femoral or crural ring, closed by the septum 

 crurale. 



The femoral or crural ring (Fig. 452) is the upper opening of the femoral 

 canal, and leads into the cavity of the abdomen. 1 It is bounded in front by 

 Poupart's ligament and the deep crural arch ; behind by the pubes, covered by 

 the Pectineus muscle, and the pubic portion of the fascia lata ; internally, by 

 Gimbernat's ligament, the conjoined tendon, tne transversalis fascia, and the 

 deep crural arch ; externally, by the femoral vein, covered by its sheath. The 

 femoral ring is of an oval form, its long diameter, directed transversely, mea- 



1 This ring, like the crural canal, is a morbid or an artificial product. " Each femoral hernia 

 makes for itself (for neither outlet exists in the natural anatomy of the region) a crural canal, 

 and a crural (femoral) ring." CALLENDEB, op. tit., p. 40. 



