PRACTICAL CONSIDERATIONS : ABDOMINAL HERNIA. 1771 



ing of the inner deeper fibres of Poupart's ligament, which turn upward and inward 

 from the crest of the pubes in front of the insertion of the conjoined tendon and pass 

 behind the internal pillar of. the external ring to be inserted into the anterior sheath 

 of the rectus and into the linea alba (Fig. i486); these fibres protect the inner and 

 posterior wall of the canal in the angle between the pubes and the rectus muscle, and 

 as far outward as corresponds to the inner third of the external ring in males and the 

 inner half in females ( Malgaigne, quoted by Macready) ; (c) by the conjoined tendon, 

 which becomes thinner and weaker as it leaves the mid-line. 



It will be seen, therefore, that there is a space between the outer edge of the 

 rectus and the epigastric artery in which the abdominal wall is very thin, contains no 

 muscular layer, and is weakened anteriorly by the gap in the external oblique apo- 

 neurosis at 'the external ring, especially at its upper and outer angle, the posterior 

 wall of the canal at this point not being reinforced by the presence of the conjoined 

 tendon or CoUes's ligament (Fig. 1485). This "thin spot," lying thus partly behind 

 the external ring, is bounded internally by some aponeurotic fibres of the trans- 

 versalis muscle running from the upper surface of the pubes to the rectus (/a/x apo- 

 jieurotica ingiimalis) and externally by similar fibres running down from the same 

 muscle, encircling the inner border of the internal ring and fusing with the inner 

 surface of Poupart's ligament [ligmnentum interfoveolare) (Fig. 1493)- When 

 these two structures are broad the thin spot is narrow, and vice versa (Spalteholz). 



Fig. 1493- 



Rectus 



Deep epigastric artery 



Interfoveolar or 



Hesselbach's ligament 



Weak area 



Conjoined tendon 



Muscular fibres 



Lower end of Poupart's ligament 



Urachus- 



Bladder 



Poupart's ligament 



.Transversalis muscle 



Spermatic vessels 

 External iliac artery 

 External iliac vein 



Deep epigastric artery (cut) 



V'as deferens 



Femoral ring 

 Gimbernat's ligament 



Dissection of posterior surface of anterior abdominal wall, showing relations of conjoined tendon and its expansions 



to internal abdominal ring. 



It is perhaps intrinsically weaker than any portion of the external hernial fossa 

 (Treves), but the infundibuliform depression at the entrance to the inguinal canal, 

 the presence of the canal itself, and the many anomalies associated with the descent 

 of the testis far outweigh this weakness as factors in the production of hernia. 



A direct inguinal hernia may escape through (a) the inner inguinal fossa, be- 

 tween the plica epigastrica and the plica hypogastrica, which corresponds in situation 

 to the outer part of the posterior wall of the inguinal canal, — i.e., to that part formed 

 by the transversalis fascia ; it would go around the outer edge of the conjoined 

 tendon, enter the inguinal canal a little below the internal ring, and have the same 

 coverings as the oblique hernia, except that the general transversalis fascia would re- 

 place the infundibuliform fascia ; or {b') the outer part of the supravesical fossa, 

 between the plica hypogastrica and the plica urachi, — the outer and deepest part of 

 which corresponds to the external ring, — in which case it might either also go around 

 the outer edge of the conjoined tendon and triangular ligament, or, if those struc- 

 . tures are thin and poorly developed, might carry them with it, so that its coverings 

 would be (i) extraperitoneal connective tissue, (2) transversalis fascia, (3) con- 

 joined tendon, (4) Colles's ligament, (5) intercolumnar fascia, (6) superficial fascia, 

 (7) skin. The spermatic cord usually lies on the outer side of the sac. As many 

 such herniae practically issue through the lowest part of the linea semilunaris, it has 

 been proposed to call them veyitro-inguinal hernits. They have no such essential 



