840 



ILIAC ARTERIES. 



structure converted by condensation or removal 

 of its adeps into an expansion ; to me it appears 

 that the view taken of its nature by Scarpa is cor- 

 rect, not in the sense that it is a prolongation of 

 the fascia lata, but that it is of the same nature, 

 and that it is to the abdomen the same structure 

 which the fascia lata is to the thigh ; it is a 

 question entitled to consideration only for ac- 

 curacy's sake, but I have frequently verified the 

 inferior connections of this expansion such as 

 they have been detailed, and further it appears 

 to me that it is not properly continuous with 

 the superficial fascia of the thigh, for if it be 

 detached from the aponeurosis of the oblique 

 muscle and the crural arch without injury to its 

 connection with the fascia lata, and be then 

 held perpendicular to the latter, the superficial 

 fascia of the thigh may be removed from the 

 angle which it will thus form with the fascia 

 lata, and its connection still remain perfect : 

 a favourable subject and a careful dissection 

 will certainly be required for the purpose, but 

 this circumstance will not invalidate the con- 

 clusion ; it is also to be recollected in making 

 the dissection, that the fascia detaches processes 

 over the inguinal lymphatic glands. 



The structures of the second order of parts 

 concerned with our subject, are the aponeurosis 

 x of the external oblique muscle, the internal 

 oblique and the transversalis muscles; of these 

 the first, which is immediately beneath the 

 fascia, extends over the entire anterior wall of 

 the fossa reaching from the linea semilunaris 

 above to the crural arch below ; internally it is 

 united with that of the other side in the linea 

 alba, and inferiorly it forms the crural arch by 

 its border, which is attached externally to the 

 superior anterior spinous process of the ilium, 

 internally to the spinous process of the pubis, 

 and in the interior to the iliac fascia and the 

 fascia lata. The direction of this band is to be 

 borne in mind, for it does not run directly from 

 one of these points of bone to the other ; but 

 it descends toward the thigh, and recedes from 

 the surface at the same time that it passes in- 

 ward, hence it is concave both forward toward 

 the surface and upward toward the abdomen ; 

 the cause of this direction is its connection 

 inferiorly and posteriorly with the fascia lata 

 and the fascia iliaca. The aponeurosis consists 

 primarily of tendinous fibres which run in the 

 same direction as the fibres of the muscle, i. e., 

 downward and inward, parallel to each other, 

 and also to the crural arch, though rather con- 

 verging toward it internally, and thereby form 

 a tendinous expansion ; the longitudinal fibres 

 of the aponeurosis are crossed by others which 

 run downward and outward ; these are very 

 irregular in number and do not interlace with 

 the former, to which they are superficial ; hence 

 the aponeurosis does not possess great strength 

 in the transverse direction, and its longitudinal 

 fibres are liable to be separated, and deficien- 

 cies to be thereby formed in the aponeurosis, 

 which are not unfrequently to be observed. 

 The superficial inguinal ring is seated in the 

 aponeurosis ; this aperture, for the particulars of 

 which see the articles ABDOMEN and HERNIA, 

 is of variable form and size ; in some cases it 



is elliptical, in others triangular ; in the male 

 it is larger than in the female; its position is 

 oblique, the longer diameter inclining from the 

 pubis upward and outward toward the superior 

 anterior spinous process of the ilium ; its 

 actual length is extremely variable, in some 

 instances not amounting to half an inch, in 

 others exceeding an inch. 



The inferior part of the internal oblique and 

 of the transversalis muscles, which alone is 

 concerned in the anatomy of this part of the 

 abdominal wall, may be distinguished into two 

 parts, viz., their muscular portion and their 

 aponeurosis. The muscles are both, but more 

 particularly the latter, very thin, though of 

 great width; they are placed the one within the 

 other, and the internal oblique, which is super- 

 ficial to the transversalis, also descends a good 

 deal lower, so that its inferior margin approaches 

 very close to the crural arch, leaving only suf- 

 ficient space between them for the escape of 

 the spermatic process, which it covers beneath 

 the aponeurosis of the external oblique, and 

 which in some instances passes between its- 

 fibres,* while the margin of the transversalis is 

 at some distance from the arch, and rarely 

 covers the process, at least to any extent, the 

 process escaping from the deep ring, for the 

 most part below the margin of the muscle ; 

 Cloquet has even seen the margin of the muscle 

 so far as two fingers' breadth above the point of 

 escape of the cord, arid its fibres are usually 

 pale, fine, and scattered. The muscular fibres 

 of the lower part of the two muscles are at- 

 tached to the anterior extremity of the crest of 

 the ilium and to its spinous process, also to the 

 superior aspect of the outer part of the crural 

 arch, the oblique to nearly the outer half of 

 the arch, the transverse to the outer third or 

 fourth, but the ultimate attachment of the 

 latter is to the surface of the fascia iliaca above 

 the arch, to which they adhere very intimately 

 as they pass forward from the fascia ; they run 

 inward nearly transversely, but convex forward 

 in proportion to the prominence of the abdo- 

 men, those of the oblique over the deep ring, 

 and the spermatic process within the inguinal 

 canal, those of the transverse above the ring, 

 until they have both passed that point ; they 

 then descend along the inside of the process, 

 and at the same time recede from the surface so 

 that they become posterior to it, and terminate 

 as they descend in a thin irregular aponeurotic 

 expansion common to the fibres of both mus- 

 cles, and thence denominated " the conjoined 

 tendon ;" though designated by an especial 

 name, this is in reality only the inferior part of 

 the general conjoined tendon of the two mus- 

 cles which terminate between the umbilicus 

 and the pubis in a common expansion ; this is 

 placed superficial to the rectus muscle, and is 

 inserted into the linea alba, the anterior margin 

 of the crest of the pubis as far as its spinous 

 process, and thence outward into the pectineal 

 line of the bone, there forming the " conjoined 

 tendon" of the anatomy of hernia. This struc- 

 ture is situate behind the spermatic process, 



* Cloquet. 



