250 MUSCLES OF THE ABDOMEN. 



the thigh, a form which is given to it by its connection with the fascia lata 

 of the limb. 



Above the crest of the pubes the fibres of the aponeurosis, separating from 

 the inner part of Poupart's ligament, leave between them an oblique open- 

 ing, the superficial or external abdominal ring, through which passes the 

 spermatic cord in the male, and the round ligament in the female. The 

 direction of this opening is upwards and outwards, its base being formed by 

 the pubic crest, and its sides by the two sets of diverging fibres called the 

 pillars. The upper or internal pillar is attached to the anterior surface of 

 the symphysis pubis, interlacing with the corresponding fibres of the opposite 

 side ; the lower or external pillar is formed by Poupart's ligament, near its 

 attachment to the spine of the pubic bone. 



A portion of the aponeurosis, which is reflected backwards and outwards 

 along the pectineal line from the attachment of Poupart's ligament to the 

 spine of the pubes, constitutes a small triangular process with a curved 

 external border, not far distant from the femoral ring. This receives the 

 name of Gimbernafs ligament. Some curved fibres, directed across the 

 diverging pillars and uniting them together, are named intercolumnar. A 

 few of these, descending upon the spermatic cord from the margin of the 

 opening, are prolonged upon that structure as a delicate fascia, named 

 intercolumnar fascia. The intercolumnar fibres may be regarded as the 

 lowest of a series of tendinous fibres, which cross the aponeurosis of the 

 external oblique muscle somewhat obliquely over a considerable extent of its 

 surface, and the strongest of which proceed from near the superior spine of 

 the ilium and upper part of Poupart's ligament. 



The deep or internal oblique muscle (ascending or small oblique), placed 

 under cover of the external oblique, arises by fleshy fibres from the external 

 half or two-thirds of the deep surface of Poupart's ligament, from the iliac 

 crest for two-thirds of its length, and by some fibres from the posterior 

 aponeurosis of the transversalis muscle, in the angle between the crest of 

 the ilium and the outer margin of the erector spinae muscle. From those 

 attachments the fibres, spreading somewhat, pass to be inserted as follows : 

 the most posterior fibres pass upwards and forwards to the lower margins of 

 the cartilages of the last four ribs, where they are inserted in the same plane 

 with the internal intercostal muscles ; those arising further forwards from 

 the crest of the ilium pass, the upper more obliquely, and the rest more 

 horizontally, forwards to end in an aponeurosis in front of the abdomen ; 

 those from the front part of the crest extend horizontally inwards to the 

 same aponeurosis ; while the fibres from Poupart's ligament, usually paler 

 than the rest, arch downwards and inwards over the spermatic cord, or the 

 round ligament of the uterus, and end in tendinous fibres common to them 

 and the lower part of the transversalis muscle, and hence known as the 

 conjoined tendon of these muscles ; through the medium of this tendon they 

 are attached to the front of the pubes, and for some distance along the 

 pectineal line, behind and to the outside of Gimbernat's ligament. The 

 spermatic cord and round ligament pass under the arched lower border of 

 the internal oblique and transversalis muscles through the internal or deep 

 abdominal ring. 



The aponeurosis may be regarded as the expanded tendon of the muscle 

 continued inwards in front ; it extends from the margin of the thorax to 

 the pubes, and is wider at the upper than at the lower end. At the outer 

 border of the rectus muscle this structure divides into two layers, one 

 passing before, the other behind, that muscle ; and the two reunite at its 



