578 THE ARTERIES 



of the obturator and the corresponding vessel of the opposite side. This branch, 

 though usually small, is occasionally considerably enlarged, when its exact course be- 

 comes of great interest to the surgeon. Thus it may descend immediately internal to 

 the vein, and therefore external to the femoral ring, or it may pass inwards in front 

 of the femoral ring and turn downwards either l)ehind the os ]Hibis or immediately 

 behind the free edge of Gimbernat's ligament, in wliich situation it would be 

 exposed to injury in the operation for the relief of a strangulated femoral hernia, 

 (c) The muscular, which 'supply the rectus and the oblique and transverse 

 muscles of tlie abdomen, and anastomose with the lower intercostal and the lumbar 

 arteries, (rf) The cutaneous, which pierce the rectus, and supply the skin, anas- 

 tomosing with branches of the superficial epigastric. And (e) the terminal, 

 Avhich anastomose above the umbilicus with the superior epigastric branch of the 

 internal mammary. 



Variations. — (A) Tlie epigastric may come off from the external iliac higher than usual ; 

 it has been met with arising as much as two inches and a half above Poupart's ligament. (B) 

 It may arise from the femoral below Poupart's ligament, or even from the profunda. (C) It 

 may arise as a common trunk with the circumflex iliac. (D) It is sometimes double. (E) It may 

 arise from the obturator, or conver.selj' it may give oif the obturator artery. This variation is 

 due to the enlargement of the normal anastomosis of the epigastric and obturator through their 

 pubic branches. It is of considerable importance to the surgeon, since the obturator artery, 

 when given off from the epigastric, may run either external or internal to the femoral ring to 

 reach the obturator foramen. This abnormal origin of the obturator is said to occur once in eveiy 

 three subjects and a half; but the abnormal artery only courses round the inner side of the ring — 

 in which situation it is liable to injury in the operation for femoral hernia — in exceptional cases. 

 According to Langton (Holden's 'Anatomy '), the chances are about seventy to one against this 

 occurring. But even when it takes the abnormal course, it lies a line and a half or so from the 

 margin of the ring, and will probably escape injury in the division of the stricture if several short 

 notches are made in jjlace of a single and longer incision. 



(2) The Deep Circimflex Iliac Artery 



The deep circumflex iliac arises from the outer side of the external iliac 

 artery, either opposite the epigastric or a little below the origin of that vessel. It 

 courses upwards and outwards just above the lower margin of Poupart's ligament, 

 lying between the fascia transversalis and the peritoneum, or at times in a fibrous 

 canal formed by the union of the fascia transversalis with the iliac fascia. Near the 

 anterior superior spine of the ilium, it perforates the transversalis, and then courses 

 between that muscle and the internal oblique, along and a little above the crest of 

 the ilium. It finally divides into an ascending branch, which anastomoses with the 

 lumbar and lower intercostal arteries, and a marginal branch which runs backwards 

 to anastonrose with the ilio-lumbar artery. It is accompanied by two veins. These 

 unite into one trunk, which then crosses the external iliac artery to join the external 

 iliac vein. 



The deep circumflex iliac artery gives off the following branches: — (a) 

 Muscular branches, which supply the psoas, iliacus, sartorius, tensor fasciae fem- 

 oris, and the oblique and transverse muscles of the abdomen. One of these branches, 

 larger than the rest, usually arises about an inch behind the anterior superior spine 

 of the ilium and ascends perpendicularly between the transversalis muscle and the 

 internal oblique. It has received no name but is important to the surgeon, as it 

 indicates the intermuscular plane between the two muscles, {h) Cutaneous 

 branches, which supply the skin over the course of the vessel, and anastomose 

 with the superficial cireumfiex iliac, the gluteal, and the ascending branch of the 

 external circumflex. 



Variations. — (A) The circumflex iliac, like the epigastric, may be given oiT from the external 

 iliac higher than normal, th(.»ugh seldom if ever as high as the latter. (B) More rarely it may 

 come oft" from the femoral below Poupart's ligament. (C) It may arise as a common trunk with 

 the epigastric. (D) It may be doubb. 



