ILIAC ARTERIES. 



839 



external iliac. It forms a stratum of some 

 thickness and considerable resistance, deserving 

 of much attention in a practical point of view; 

 there are imbedded in it immediately above the 

 crural arch, and superficial to the artery, one or 

 more lymphatic glands; the genito-crural nerve 

 also descends enclosed in this structure, at the 

 outside of the artery. Beneath the investment, 

 and immediately above the crural arch, an ex- 

 pansion of limited extent, presenting frequently 

 a true fibrous or aponeurotic character, arises 

 from the front of the vessels, and passing 

 forward becomes identified with the fascia 

 transversalis upon its internal surface; thus 

 connecting the vessels to the anterior part of the 

 superior aperture of the femoral sheath, and 

 closing the interval between these parts, which 

 otherwise would be unguarded. 



In the second place the artery is covered 

 anteriorly through about four-fifths of its course 

 by the peritoneum of the iliac fossa ; in th6 

 inferior fifth, i. e., for from half to three-fourths 

 of an inch immediately above the crural arch, 

 the membrane passing from the front of the 

 artery to the anterior wall of the abdomen 

 leaves the iliac artery uncovered ; and hence 

 the practical inference that the external iliac 

 artery may be tied without disturbing the 

 peritoneum. 



Beneath the peritoneum the artery is crossed 

 at the inferior part of its course by the sper- 

 matic vessels, and at the superior, upon the 

 right side very frequently by the ureter. 



Thirdly, the viscera of the iliac fossa on the 

 one hand, or of the pelvis on the other, ac- 

 cording to circumstances, cross or overlap it; 

 on the right, the coecum and the termination 

 of the ileum ; on the left, the sigmoid flexure 

 and the commencement of the rectum, and on 

 both sides the small intestines are placed in front 

 of it. And when the viscera of the pelvis become 

 distended and rise from the cavity they overlap 

 it from that side. 



The third relation of the artery in front is 

 the anterior wall of the iliac region ; the details 

 of this it is not proposed to examine at length, 

 but only so far as they may be concerned in 

 the relations of the artery ; the structures com- 

 posing the wall being numerous, they may be 

 conveniently arranged into three sets, viz., the 

 superficial, the intermediate, and the deep or 

 lining structures. 



The superficial structures are three, the 

 skin, the subcutaneous cellular tissue, and the 

 fascia. Of these the first does not require to 

 be dwelt upon ; the second is subject to much 

 variety in its condition ; it forms a stratum of 

 considerable thickness in every case ; when, 

 however, the superficial cellular structure of 

 the body is charged with much adeps, it then 

 forms an uniform and thick stratum of fat 

 without any distinction into laminae ; this is 

 best exemplified at the early periods of life, 

 particularly in children cut off by an acute 

 disease ; when, on the contrary, the body is 

 emaciated, it forms a condensed cellular "ex- 

 pansion much thinner than in the former case, 

 and divisible frequently into laminae. This 

 structure is continued from the iliac over the 



other regions of the abdomen, downward upon 

 the thigh, and in the middle line upon the 

 spermatic process of the male and the organs 

 of generation. Numerous superficial vessels 

 are contained in and ramify through it; these 

 are derived from several sources, but that which 

 is proper to the iliac region is the superficial 

 epigastric artery which ascends from the 

 femoral superficial to the aponeurosis of the 

 external oblique muscle and intermediate to 

 the inguinal rings. 



Beneath the subcutaneous stratum is the 

 third superficial structure, the fascia ; this is a 

 thin dense expansion by which the external 

 oblique muscle and its aponeurosis are covered ; 

 it is not confined to the abdomen, but is con- 

 tinued into a similar expansion upon the ad- 

 joining regions whether upward or downward ; 

 it adheres closely to the muscular portion of 

 the oblique, particularly at the junction of the 

 muscular fibres with the aponeurosis along the 

 linea semilunaris, but its connection to the 

 aponeurosis itself is more free, an extensible 

 and delicate cellular tissue being interposed. 

 Hence it is easily detached from the latter ; it 

 is most dense, fibrous, and strong upon the 

 iliac region ; as it ascends thence it becomes 

 less dense and fibrous, and assumes more of a 

 simply condensed cellular character ; it is not 

 equally distinct in every subject, in all it can 

 be recognized at the crural arch, and for some 

 distance above it, but as it recedes from the 

 arch it frequently seems to be gradually re- 

 solved and to cease. Below, it is attached 

 posteriorly to the outer edge of the crest of the 

 ilium, and along this line it meets the insertion 

 of the fascia lata of the back of the thigh ; in 

 front between the superior anterior spinous 

 process of the ilium and the spinous process of 

 the pubis it descends over the crural arch, having 

 only a cellular connection to it, and being 

 separable with ease from it, as well as from 

 the aponeurosis of the oblique ; immediately 

 below the arch it is united to the superficial 

 surface of the fascia of the thigh, both externally 

 and internally, on the latter side passing back 

 to the pectineal line of the pubis, into which it 

 is inserted along with the pubic portion of the 

 fascia lata; in the interval between the spinous 

 processes of the pubis it is prolonged down- 

 ward upon the spermatic processes, and is 

 continued upon them in the form of a sheath 

 into the scrotum, where it invests the testicle ; it 

 is very thin and transparent upon the spermatic 

 process. The existence of this structure, to 

 which attention appears to have been first 

 directed by Camper, can always be demon- 

 strated however fat or young the subject may 

 be, though, as has been stated, it is not always 

 equally manifest ; it seems distinct from th 

 subcutaneous cellular structure, which frequently 

 forms a uniform and thick stratum of fat be- 

 tween it and the skin. Different views have 

 been taken of its nature ; by Scarpa it is re- 

 garded as a prolongation of the fascia lata of 

 the thigh, while others and the majority consider 

 it as a continuation of the superficial fascia, so 

 called, of the same part, and formed by the deep 

 stratum of the abdominal subcutaneous cellular 



