404 ABDOMEN 



1. The intercostal and lumbar arteries. 



2. The inferior epigastric. 



3. The deep circumflex iliac. 



4. The superior epigastric. 



5. The musculo-phrenic. 



The intercostal arteries of the two lower spaces are pro- 

 longed forwards between the internal oblique and the trans- 

 versus abdominis. They have already been noted accom- 

 panying the corresponding nerves. In front they anasto- 

 mose with branches of the epigastric arteries, whilst inferiorly 

 they effect communications with the lumbar arteries. 



The abdominal branches of the lumbar arteries ramify between 

 the same two muscles as the preceding vessels, but at a lower 

 level in the abdominal wall. Anteriorly they anastomose with 

 branches of the inferior epigastric artery ; above with the 

 intercostal arteries ; and below with the deep circumflex iliac 

 and the ilio-lumbar arteries. 



Arteria Epigastrica Inferior (O.T. Deep Epigastric Artery). 

 This branch of the external iliac is a vessel of some size. 

 It takes origin about a quarter of an inch above the 

 inguinal ligament. At present it is seen shining through the 

 fascia transversalis and forming the lateral boundary of 

 Hesselbach's triangle. Divide the fascia transversalis along 

 its course and note the two veins which accompany the artery. 

 Study the course and relations of this vessel. At first it 

 runs medially for a short distance between the inguinal 

 ligament and the abdominal inguinal ring, and then chang- 

 ing its direction it is carried upwards and medially on the 

 medial side of the ring. Reaching the deep surface of the 

 rectus it enters the rectal sheath, and proceeding vertically 

 upwards, ends, near the lower margin of the thorax, in 

 branches which sink into the substance of the muscle and 

 anastomose with the superior epigastric. 



In the first part of its course, the deep epigastric lies in the 

 extra -peritoneal fat between the peritoneum and the fascia 

 transversalis. Soon, however, it pierces the fascia, and, passing 

 in front of the linea semilunaris, ascends between the rectus 

 muscle and the posterior lamella of its sheath. These are 

 its immediate relations, but there are others of equal importance, 

 viz. (i) as it runs upwards it lies close to the medial side of the 

 abdominal inguinal ring; (2) as the spermatic cord traverses 

 the inguinal canal it lies in front of the artery, only separated 



