THE ABDOMEN. 



379 



The superior epigastric artery is one of the two terminal branches of the 

 internal mammary. The other is the musculophrenic, which skirts the edge of 

 the thorax. The internal mammary divides opposite the sixth interspace, and the 

 superior epigastric, leaving the thorax at the lower edge of the seventh rib, enters 

 the sheath of the rectus muscle and a few inches lower down enters the substance 

 of the muscle, speedily breaking up into small branches. It is only large in size 

 up toward the thorax, where we have seen it cut by a stab-wound, causing dan- 

 gerous hemorrhage. It may also be wounded in operations and is to be sought 

 for between the muscle and its posterior sheath, on a line continued downward 

 from a point one centimetre to the outer side of the edge of the sternum. 



The deep epigastric artery arises from the external iliac at Poupart's liga- 

 ment and curves inward and upward between the peritoneum and transversalis 

 fascia. It reaches the edge of the rectus below a line joining the femoral artery 



Sixth intercostal nerve 

 Seventh nerve 



Eighth nerve 

 Ninth nerve 

 Tenth nerve 



Eleventh nerve 

 Twelfth nerve 



Iliohypogastric nerve 



Ascending branch 



Deep circumflex iliac artery 



Ilio-inguinal nerve 



Superior epigastric artery 



The sheath of the rectus has 

 been cut along its outer edge 

 and the muscle turned inward 



Umbilicus 



Deep epigastric artery. 



FIG. 391. The nerves and blood-vessels of the anterior abdominal wall. The nerves are seen piercing the 

 posterior layer of the sheath of the rectus to enter the muscle. The external and internal oblique have been removed 

 exposing the nerves lying on the transversalis. 



at Poupart's ligament with the umbilicus. Opposite the fold of Douglas (linea 

 semicircularis) it reaches the middle of the rectus, pierces the transversalis fascia, 

 and enters the substance of the muscle. It sends branches to the outer edge of 

 the muscle which are quite large and bleed freely when cut. It anastomoses 

 above with the superior epigastric. It is a most important artery, as it is liable to 

 be wounded in operations for appendicitis, etc. If cut it will require a ligature, 

 and if pierced by a needle will bleed freely. As it passes upward from Poupart's 

 ligament it lies to the upper and outer side of the femoral canal and may be 

 wounded if the herniotomy knife is turned in that direction. A little higher it 

 crosses the inguinal canal almost midway between the internal and external 

 abdominal rings. An oblique inguinal hernia enters the canal to the outer side 

 of this artery and a direct hernia to its inner side. The fold of the obliterated 

 hypogastric artery is to its inner side. 



The deep circumflex iliac artery arises from the external iliac almost oppo- 

 site the deep epigastric and passes outward along the inner side of Poupart's ligament 



