428 THE MUSCLES AXD FASCIA 



oblique muscle. This opening is oblique in direction, corresponding with tta 

 course of the fibres of the aponeurosis, is somewhat triangular in form, and usuall} 

 measures about an inch (2.5 cm.) from base to apex and about half an incl: 

 (1.25 cm.) transversely? It gives passage to the spermatic cord in the male anc 

 to the round ligament in the female. It is bounded below by the crest of the QJ 

 pubis; above, by a series of curved fibres, the external spermatic or the inter- 

 columnar fibres which pass across the upper angle of the ring, thus increasing it; 

 strength; and on each side, by the margins of the opening in the aponeurosis 

 which are called the columns or pillars of the ring. 



The external pillar (cms inferius) is inferior from the obliquity of its direction 

 It is stronger than the internal pillar; it is formed by that portion of Poupart': 

 ligament which is inserted into the spine of the os pubis; it is curved so as to forn 

 a kind of groove, upon which the spermatic cord rests. 



The internal pillar (crus superius), a broad, thin, flat band, is formed by the 

 fibres of the aponeurosis which are inserted into the symphysis pubis. 



The intercolumnar fibres (fibrae intercrurales) (Fig. 320) are a series of curvec 

 tendinous fibres, which arch across the lower part of the aponeurosis of the Externa 

 oblique. They have received their name from stretching across between the 

 hjK)! pillars of the external ring, describing a curve with the concavity downward 

 They are much thicker and stronger at the outer margin of the external ring 

 where they are connected to the outer third of Poupart's ligament, than internally 

 where they are inserted into the linea alba. They are moijelptrongly developec 

 in the male than in the female. The intercolumnar fibres increase the strengtl 

 of the lower part of the aponeurosis, and prevent the divergence of the pillar; 

 from each other. 



These intercolumnar fibres as they pass across the external abdominal rin^ 

 are themselves connected together by delicate fibrous tissue, thus forming a fascia 

 the intercolumnar fascia or the external spermatic fascia, which, as it is attachec 

 to the pillars of the ring, covers it in. This intercolumnar fascia is continuec 

 down as a tubular prolongation around the outer surface of the cord and testi: 

 or of the round ligament, and encloses them in a distinct sheath. 



Applied Anatomy. -The sac of an inguinal hernia, in passing through the external abdomina 

 ring, receives an investment from the intercolumnar fascia. If the finger is introduced a shor 

 distance into the external abdominal ring and the limb is then extended and rotated outward 

 the aponeurosis of the External oblique, together with the iliac portion of the fascia lata, wil 

 be felt to become tense, and the external ring much contracted; if the limb is. on the contrary 

 flexed upon the pelvis and rotated inward, this aponeurosis will become lax and the externa 

 abdominal riny sufficiently enlarged to admit the finder with comparative ease; hence the patieni 

 should always be put in the latter position when the taxis is applied for the reduction of ar 

 inguinal hernia in order that the abdominal walls may be relaxed as much as possible. 



Poupart's Ligament (ligamentum inguinale). The portion of Poupart's ligament 

 in front of the crural ring is called the superficial femoral arch. Poupart's ligamenl 

 is the lower border of the aponeurosis of the External oblique muscle, and extends 

 from the anterior superior spine of the ilium to the pubic spine. From this 

 latter point it is reflected to the iliopectineal line for about half an inch, thus 

 forming Gimbernat's ligament. Its general direction is curved downward toward 

 the thigh, where it is continuous with the fascia lata. Its outer half is rounded 

 and oblique in direction and gives partial origin to the Internal oblique and 

 Transversal is muscles. Its inner half gradually widens at its attachment to the 

 os pubis, is more horizontal in direction, and lies beneath the spermatic cord. 

 Nearly the whole of the space included between the femoral arch and the innom- 

 inate bone is filled "in by the parts which descend from the abdomen into the thigh 

 (Fig. 328). These will be referred to again on a subsequent page. 



