Arteries of the Trunk. 421 



The aorta abdoniinaliS (see also Figs. 499 and 033) runs downward on the 

 anterior surface of the lumbar vertebrae, a little to the left of the median plane. It is directly 

 covered in front by the corpus pancreatis, the pars inferior duodeni and the peritonaeum, lies 

 on the left side of the v. cava inferior and divides in front of the lower margin of the 4tii lumbar 

 vertebra into the aa. iliacae communes dexti-a et sinistra. Its branches are divisible into rami 

 parietales (to the walls of the abdomen) and rami yisccrales (to the abdominal viscera). 



A. Rami parietales: 



1. A. phreuica inferior, paired, arises in front of the 12tii thoracic vertebra, separated 

 fi-om, or in 'common with, that of the other side, goes upward, forward and lateralward on 

 the inferior surface of the pars lurabalis diaphragmatis (on the right side behind the foramen 

 venae cavae) and helps to supply the diaphragm. Branches: 



a) Rami suprarenales superiores, from the first part of the artery, to the adrenal. 



2. Aa. lumbales I IV (0.,T. lumbar arteries) (see also Fig. 462), paired, go off, usually 

 at a right angle, from the posterior wall, one in fi-ont of in body of each of the 1st _ 4111 

 lumbar vertebrae ; they run backward on the lateral surface of the same, covered by the crura 

 diaphragmatis and the origins of the m. psoas major, and pass through the m. quadra tus lumborura 

 to the muscles and to the skin of the lateral wall of the abdomen. Eacli gives off one branch : 



a) Ramus posterioi-, corresponds exactly to the r. posterior of an a. intercostalis (see p. 419); 

 it gives oft' a ramus spinalis and goes to the muscles and skin of the lumbar region. 



3. A. sacralis media (middle sacral artery) (see also Figs. 470 and 471), impaired, from 

 the posterior wall of the aurta a little above the bifurcation, extends downward, somewhat tortuous, 

 in the median plane in front of the Sth lumbar vertebra, sacrum and coccyx. It gives off branches 

 to the neighboring bones, muscles, nerves and to the rectum and ends in a vascular skein, the 

 glomus coccyfjeum (not illustrated), situated beneath the tip of the coccyx. Branch: 



a) A. lumhalis ima runs lateralward and downward, one on each side, upon the body of 

 the 5th lumbar vertebra to the mm. psoas major and iliacus. 



B. Rami riscerales: 



1. A. suprareiialis media (middle suprarenal artery), paired, arises a little below the 

 a. coeliaca tmd runs directly in front of the crus mediale diaphragmatis to the adrenal. 



2. A renalis (renal artery), paired, arises nearly at a right angle at the level of the 

 1st lumbar vertebra (or somewhat lower), rims transversely in front of the crus mediale dia- 

 phragmatis (on the right side behind the v. cava inferior) behind the v. renalis and sends its 

 branches in fi-ont of and behind the pelvis of the kidney to the substance of the kidney (see also 

 Ilg. 638). Variations in the origin and number of the renal arteries are fi-erpient. Each, by 

 means of small branches to the tunica adiposa of the kidney, anastomoses with the aa. phrenica 

 inferior j^ lumbales, suprarenales, spermaticae intemae and mesentericae. Each gives off also: 



a) A. suprareiialis inferior to the adrenal. 



3. A. spermatica interna (0. T. spermatic artery) (see also Figs. 464 and 465), paired, 

 arises, at an acute angle, at the level of the 2id lumbar vertebra, runs downward, lateralward 

 and forward (on the right side in front of the v. cava inferior) upon the mm. psoas major and 

 minor, in front of the ureter, behind the peritonaeum, gives off in its course fine branches to 

 the tunica adiposa of the kidney, to the ureter and to the lymph glands and approaches the 

 lateral margin of the pelvic inlet. Thence it is distributed differently in the two sexes. 



In the male, as the a. testicularis (see also Figs. 467, 499 and 650) it goes upon the 

 m. psoas major, in fi-ont of the a. and v. iUaca externa to the annulus inguinalis abdominalis and, 

 surrounded by the plexus pampiniformis, in the spermatic cord to the epididymis and testicle. 



In the female, as the a. ovarica (see Figs. 471, 472 and 503) it crosses the a. and 

 V. iliaca externa, nearly in ft-ont of the ureter, enters mto the lig. suspensorium ovarii, surrounded 

 by the plexus pampimformis, runs along the anterior margin (margo mesovaricus) of the ovary, 

 gives off branches to it and forms a broad anastomosis with the ramus ovarii of the a. uterina. 



4. A. coeliaca (0. T. coeUac axis) (see also Fig. 464), unpaired, from the anterior wall 

 between the \2^^ thoracic and the l^t lumbar vertebra, is short, and divides at the upper 

 margin of the corpus pancreatis into three branches. 



a) A. gastrica sinistra -{0. T. gastric or coronary artery) (see Figs. 464 and 465), bends 



forward and '.upward in the plica gastropancreatica to the right side of the cardia 

 and runs in the omentum minus, along the curvatura minor of the stomach, to the 

 right and downward. Small branches to the oesophagus (rami oesophagei), larger 

 ones to the anterior and posterior walls of the stomach and to the omentum minus. 



b) A. hepatica (hepatic arteiy) (see Figs. 464 and 465) runs upon the right crus mediale 



diaphragmatis at the upper margin of the pancreas behind and below the vestibulum 

 bursae omentalis to the left posterior surface of the pylorus. Branches: 

 ba) A. gastrica dextra (0. T. pyloric artery) arises at the pylorus and runs between the layers 

 of the omentum minus along the curvatura minor to the left; it unites with the a. 

 gastrica sinistra and gives off branches to the anterior and posterior walls of the stomach. 



