THE A BDOMEN 773 



and in front with the deep epigastric. Sometimes there are five 

 lumbar arteries on each side, the fifth pair coming usually from the 

 middle sacral artery. Each of these passes beneath the correspond- 

 ing common iliac vessels, and, ha\Tng furnished a dorsal branch, 

 usually to the gluteus maximus, it is distributed over the lateral 

 mass of the sacrum and ends in the iliacus, where it anastomoses 

 with the deep circumflex iliac artery. 



The lumbar veins open into the inferior vena cava, those of the 

 left side passing behind the abdominal aorta. The vessels of 

 each side are connected by a series of longitudinal anastomosing 

 veins in front of the lumbar transverse processes, and the longi- 

 tudinal vessel thus formed is called the ascending lumbar vein. 



Subcostal Artery. — This vessel is the last parietal branch of the 

 thoracic aorta. It lies below the last rib, and is in series with the 

 aortic intercostals above and the lumbar arteries below. It winds 

 roimd the side of the body of the twelfth thoracic vertebra, and 

 courses along the lower border of the twelfth rib with the subcostal 

 nerve, passing behind the external arcuate ligament of the 

 diaphragm and in front of the quadratus lumborum. This part of 

 the vessel is behind the kidney and the ascending or descending 

 colon, according to the side. Its subsequent course corresponds 

 with that of the abdominal branches of the lumbar arteries. It 

 anastomoses with the lower two intercostal arteries, the abdominal 

 branches of the lumbar arteries, the lateral or intermuscular epi- 

 gastric of the deep circumflex iliac, and the deep epigastric artery. 

 This vessel has to be borne in mind in such operations as nephrotomy, 

 nephrorrhaphy, and nephrectomy. 



The subcostal vein of each side enters the thorax behind the 

 external arcuate ligament of the diaphragm, the right opening into 

 the right azygos vein, and the left into the lower left azj'gos vein. 



Subcostal Nerve. — This is the anterior primary division of the 

 twelfth thoracic nerve, and is in series with the eleventh or last 

 intercostal. It accompanies the subcostal artery, and ultimately 

 enters the sheath of the rectus abdominis, which muscle it pierces 

 from behind forwards to become an anterior cutaneous nerve. In 

 its course it gives off an undivided lateral cutaneous or iliac branch, 

 which pierces the internal and external oblique muscles, and 

 descends over the iliac crest to be distributed to the integument of 

 the anterior part of the gluteal region. Besides this branch it 

 furnishes the following offsets: (i) dor so - lumbar to the anterior 

 primary division of the first lumbar nerve ; and (2) branches to 

 the quadratus lumborum, transversalis abdominis, internal oblique, 

 and pyramidalis abdominis. 



Lumbar Glands. — ^These are very numerous, and are divided into 

 three groups — median, and two lateral, right and left. 



The median lumbar glands are about twelve in number, and lie 

 behind the parietal peritonemn, in front of, behind, and along the 

 sides of the aorta (as high as the root of the superior mesenteric 

 artery) and inferior vena cava. A few of the lower glands lie along 



