ABDOMINAL MUSCLES. 331 



also a fascia (fascia superficialis abdominis) which covers the 

 whole tendon of the external oblique muscle, and passes from it 

 down upon the fascia of the thigh : which also connects the 

 tendon of the external oblique to the fascia of the thigh, and 

 serves to bind it down. From these connexions it is probable 

 that the tendon is in a very different situation before dissection, 

 from what it is afterwards ; as the division of these connexions, 

 necessarily made by the dissection, renders it much more loose 

 than it could have been while the parts were undivided. This 

 structure has latterly been called the crural arch. The fascia 

 which covers the tendon of the external oblique muscle, and 

 descends upon the thigh, can be examined very easily in anasar- 

 cous subjects ; as in them, the cellular membrane, which is 

 situated between this fascia and the tendon, is somewhat dis- 

 tended by the effused fluid. 



To prepare Poupart's ligament or the crural arch, for exami- 

 nation, remove carefully the cellular membrane from the tendon 

 of the external oblique, and also from the fascia of the thigh, 

 taking care not to remove any part of the fascia which passes 

 under the tendon to be inserted into the os pubis. Then make 

 an incision in the tendon of the external oblique, about three 

 inches above Poupart's ligament, parallel to it, and nearly of 

 the same length ; make a second incision from the upper end 

 of this, to the junction of the aforesaid ligament with the supe- 

 rior anterior spine of the ilium ; and a third incision from the 

 lower end to the abdominal ring. Dissect this flap carefully 

 from the internal oblique, until the spermatic chord, the cre- 

 master muscle, and the lower origin of the internal oblique, 

 are perfectly uncovered. After examining the internal surface 

 of the tendon and its insertion at the pubis, the fascia of the 

 thigh may be dissected, so that its connexion with the folded 

 edge of the tendon, and its insertion into the pubis, may also be 

 examined. 



The external oblique muscles compress the abdomen, and 

 therefore contribute to the evacuation of its contents : if the 

 diaphragm is in a passive state, they force it upwards, by 

 pressing the abdominal viscera against it ; and thus assist in 



