ABDOMEN. 



below and carrying it upwards ; the expansion 

 will then appear to arise from Poupart's liga- 

 ment, and spread over the subjacent aponeuro- 

 sis. In some subjects it is so thin as to appear 

 to be little more than the proper cellular cover- 

 ing of the muscle and its aponeurosis, but 

 in others it assumes a considerable degree of 

 density. It may be called the deep layer of 

 the superficial fascia; it deserves attention from 

 the fact that the femoral hernia, in its ascent on 

 the abdomen, lies between it and the super- 

 ficial layer. It is to this fascia that Scarpa 

 must allude under the name of " aponeurotic 

 web of the muscle of the fascia lata," and 

 hence some have called it Scarpa's fascia.* 

 The whole of the superficial fascia has been 

 called Camper's fascia, because it was first 

 fully described by that writer.f 



On the posterior wall of the abdomen, in the 

 lumbar regions, the cellular tissue is more 

 abundant and more lax; here we frequently 

 find it infiltrated with serous fluid, in conse- 

 quence of the usual supine posture of the body 

 after death. It is continuous above with the 

 subcutaneous tissue in the dorsal region, and 

 below with that in the glutoeal regions. It, 

 too, is firmly adherent along the middle line to 

 the lumbar spine anteriorly, and to the skin 

 posteriorly. 



a. Muscles and aponeuroses. The abdo- 

 minal parietes owe their thickness chiefly to 

 the muscular lamellae and the aponeurotic ex- 

 pansions, which enter into their composition. 

 In the anterior and lateral walls we find on 

 each side five pairs of muscles, of which four 

 are constantly present. These are, 1, M. obli- 

 quus externus ; 2, obliquus internus ; 3, trans- 

 versal is; 4, rectus abdominis ; 5, pyramidalis, 

 which last is frequently absent. 



1. Obliquus externus. (Obliquus descen- 

 dens ; costo-abdominal ; ilio-pubi-costo-abdo- 

 minul.) 



When the superficial fascia covering the an- 

 terior and lateral surfaces of the abdomen has 

 been dissected away, this muscle is brought into 

 view. It consists of a flat muscular portion, 

 situated superiorly and posteriorly, and of a 

 tendinous or aponeurotic lamella anteriorly and 

 inferiorly, but which is largest and strongest in 

 the latter situation. 



The muscular portion of the external oblique 

 is attached by separate fasciculi to the external 

 surfaces of the eight inferior ribs, from the 

 fifth to the twelfth inclusive. These fasciculi 

 indigitate at their attachment with similar 

 ones, of the serratus magnus, from the fifth 

 to the ninth inclusive, and of the latissimus 

 dorsi from the tenth to the twelfth. From 

 these points of attachment, described by most 

 English anatomists as the origin of the 

 muscle, the fibres pass obliquely downwards 

 and forwards, with different degrees of ob- 

 liquity, the middle fibres being the most ob- 



* Vid. Scarpa on Hernia, by Wishart, p. 22 ; 

 also Todd on Hernia, Dub. Hosp. Reports, vol. i. 

 p. 246" ; and Flood's plates of Inguinal and Femoral 

 Hernia. 



J Camper, Icones Herniarum, p. 11. 



lique, the superior taking a direction nearly 

 horizontally inwards, and the posterior ones 

 passing nearly vertically downwards. The an- 

 terior and middle fibres are inserted into the 

 outer convex border of the aponeurotic lamella 

 of the muscle, but the posterior are inserted into 

 the outer lip of the two anterior thirds of the 

 crista of the ilium by short tendinous fibres. 

 The fibres of this muscle vary considerably in 

 length, those which are highest up being the 

 shortest, the middle ones the longest, and next 

 in length the posterior fibres. The aponeurotic 

 lamella of the external oblique muscle is found 

 on the anterior part of the abdomen, both su- 

 periorly and inferiorly. In the former situa- 

 tion the aponeurosis is extremely thin and 

 weak ; it is transparent, so that the upper 

 extremity of the rectus muscle which it covers 

 is visible through it. This, too, is the narrow- 

 est portion of the aponeurosis, which increases 

 in breadth, strength, and thickness as it de- 

 scends. The aponeurosis, like the muscular 

 portion, consists of a series of fibres, for the 

 most part inclined obliquely downwards and 

 inwards, excepting the superior ones, whose 

 direction is horizontal. At several places these 

 fibres are separated from each other so as to 

 allow the subjacent muscle to be seen through 

 the interval. At various parts the tendon is 

 perforated by vascular apertures, which are oc- 

 casionally so enlarged as to admit little peri- 

 toneal prolongations to pass through them. 

 Along the middle line, from the ensiform car- 

 tilage to the symphysis pubis, the aponeurosis 

 forms an interlacement with its fellow of the 

 opposite side, and this interlacement with that 

 of the subjacent aponeuroses constitutes the 

 tendinous line called linea alba, which, as 

 Velpeau observes, may be regarded as the 

 centre in which all the fibrous elements of the 

 abdomen terminate. Just above the symphysis 

 pubis, the decussating fibres are not inter- 

 mixed in the same manner as in other parts of 

 the linea alba : there the bundle of one side 

 crosses anteriorly or posteriorly to that of the 

 other, without any union of fibres, to be in- 

 serted into the pubis of the side opposite to 

 that from which it came. 



A little above and external to the pubis, a 

 separation of the fibres of the tendon of the 

 obliquus externus takes place, leaving an 

 opening which is denominated the external 

 abdominal ring, through which the rounded 

 bundle composed of the spermatic vessels and 

 duct (the spermatic cord) passes in the male, 

 and the round ligament of the uterus in the 

 female. The aponeurotic fibres which form 

 the immediate boundaries of this opening are 

 termed the pillars of the ring, of which one is 

 superior, internal, and anterior, the other is in- 

 ferior, external, and posterior, and passes behind 

 the cord. External and inferior to this opening, 

 we observe that the aponeurosis of the external 

 oblique muscle is extended from the pubis to 

 the anterior superior spine of the ilium. On 

 the pubic side, the fibres, which are the same 

 that form the inferior pillar of the ring, are in- 

 serted into the spine of the pubis, and being 



