328 ABDOMINAL MUSCLES. 



are again united, and form a white line on. each side, which is 

 called linea semilunaris, from its curved shape. 



At the lower part of the tendon, near the os pabis, the fibred 

 are so arranged, that they form two bands more firm and 

 dense than the rest of the tendon, which are called columns : 

 these columns are separated from each other ; and the vacuity 

 between them is the abdominal ring, or aperture, for the 

 passage of the spermatic chord in males and the round ligament 

 of the uterus in females. This vacuity or aperture has an oval 

 form, which is occasioned by some additional tendinous fibres 

 at the upper part of it, that have a transverse direction* 



The uppermost of the two columns is continued obliquely 

 downwards, and is inserted into the os pubis of the opposite 

 side, near the symphysis, decussating the fibres of the cor- 

 responding column of that side. 



The lower edge of the tendon of the external oblique is 

 attached to the superior anterior spinous process of the ilium, 

 and is there blended \yith the tendinous fascia, which extends 

 down the thigh. 



From this process the edge of the tendon is extended, like 

 the chord of a bow, across the concavity formed by the os 

 ilium and os pubis, and is inserted into the pubis near its sym- 

 physis. As it proceeds from the spine of the ilium towards the 

 pubis, the edge is folded inwards, so that the membrane is 

 doubled. The portion which is turned inwards, (Gimbernat's 

 ligament,) is very small at its commencement, and continues 

 so for a great part of its extent ; but becomes much broader 

 within an inch of its termination. This broad extremity is 

 inserted into the small process of the pubis near the sym- 

 physis, and into a ridge which continues backward from the 

 process to the brim of the pelvis, so that the tendinous mem- 

 brane at this part is doubled ; the part which is turned back 

 being about an inch broad at the place of its insertion into the 

 pubis. 



This doubling forms a partial sheath near the pubis for con- 

 taining the spermatic chord, and supports it for a short distance 

 on the inside of the abdominal ring. 



