THE CRURAL SHEATH. 145 



arch, and by the opposite it is fixed to the pectineal line. In the 

 erect position of the body the ligament is almost horizontal. 



The crural or femoral sheath (fig. 56, B) is a loose tube of mem- Crural^ 

 brane around the femoral vessels. It has the form of a funnel, 

 sloped unequally on the sides. The wide part of the tube is up- 

 wards ; and the narrow part ceases about two inches below Poupart's relations : 

 ligament, by blending with the common areolar sheath of the blood- 

 vessels. Its outer border is nearly straight, and is perforated by 

 the genito-crural nerve ( 1 ). Its inner border is oblique, and is 

 pierced by lymphatics, superficial vessels, and the saphenous vein (/) ; 

 this part of the sheath appears in the saphenous opening, and is 

 connected to the falciform margin and the cribriform fascia. In 

 front of the crural sheath is the iliac part of the fascia lata. 



The sheath is continuous with the fasciae of the abdomen and how formed, 

 thigh in this way. The anterior part is a prolongation under 

 Poupart's ligament of the transversalis fascia lining the anterior 

 abdominal wall ; and the posterior part is formed externally by 

 the iliac fascia covering the psoas muscle, and internally by the 

 pubic part of the fascia lata covering the pectineus. 



Crossing the front of the sheath, beneath the arch of Poupart's Deep crural 

 ligament, is a fibrous band, the deep crural arch, which will be arc 

 noticed later on in the description of the transversalis fascia. 



Dissection (fig. 56). The student is to now open the crural Open the 

 sheath by an incision across the front, and to raise the anterior part sheath, 

 with hooks. Inside the tube are contained the femoral vessels, 

 each surrounded by its covering of areolar tissue, together with an 

 inguinal gland ; and if a piece of the areolar casing be cut out ovei Vessels have 

 both the artery and the vein, there will be an appearance of two sheath, 

 thin partitions, the one being situate on the inner side of the vein, 

 separating this vessel from the gland, and the other (J) between 

 the vein and the artery. 



Interior of tJie crural sheath. The sheath is said to be divided Contents 

 into three compartments by two partitions ; and the position of S heath. 

 the so-called septa has been before referred to one being internal 

 to the femoral vein, and the other bet ween the two large vessels. 

 In the outer compartment is contained the femoral artery (a), lying 

 close to the side of the sheath ; in the middle one is placed the three : 

 femoral vein (b) ; and in the inner space (crural canal) only a 

 lymphatic gland (c) is situated. 



The crural canal (fig. 56) is the innermost space in the interior the inner is 

 of the crural sheath : Its length is about a third of an inch, and 

 it reaches from the base of Gimbernat's ligament to the upper cornu 

 of the saphenous opening. It decreases rapidly in size from above 

 down, and is closed below. The aperture by which the space com- 

 municates with the cavity of the abdomen is named the crural ring. 



In front of the canal are Poupart's ligament and the upper end 

 of the falciform margin of the saphenous opening ; while behind it 

 is the pectineus muscle. On the outer side of the canal, but within 

 the sheath, is the femoral vein. Through this channel the intestine 

 passes from the abdomen in femoral hernia. 



D.A. L 



