4 i 4 ELEMENTARY ANATOMY. [LESS. 



The ulnar gives off the interosseous artery from the inter- 

 space between the radius and ulna, and then passes along 

 the inner side of the fore-arm to the hand, while the radial 

 traverses the front of the fore-arm obliquely to the outer 

 border of the wrist. These two arteries anastomose by a 

 pair of palmar arches (one deeper than the other) which 

 pass transversely between the ulnar and radial arteries. Of 

 course, a variety of less important branches are given off 

 at intervals, from the axillary artery and its subdivisions, 

 along the whole extent from the axilla to the palm. 



The great descending aorta gives off many small branches 

 to the air-tubes, the oesophagus, and the spaces between the 

 ribs, the last being called intercostals. After passing through 

 the diaphragm, the aorta gives off several important branches 

 to the viscera in the abdomen. Such are (i) the cosliac axis, 

 which divides into a branch to the stomach, one to the spleen, 

 and one to the liver called hepatic; (2), the superior and 

 inferior mesenteric arteries, which pass to the intestines by 

 means of those folds of membrane (mesenteries), in which, 

 as we shall see, the alimentary canal is slung ; (3), the renal 

 arteries, short and large, which pass, one on each side, to the 

 two kidneys respectively ; (4), the lumbar arteries, which 

 repeat in the abdomen the intercostals of the thorax ; and 

 lastly, the middle sacral, which is a small median vessel 

 running in front of the middle of the sacrum to the coccyx. 



The common iliac arteries into which, as has been said, 

 the abdominal aorta divides, after a short course themselves 

 subdivide, each into an internal and external iliac artery. 



The internal iliac is short, and distributes branches to the 

 viscera and muscles of the pelvis, and also to muscles of the 

 back. One small branch, called the superior vesical, passes 

 to the side of the bladder, a fibrous cord connecting it with 

 the back of the umbilicus or navel. 



The external iliac passes out into the thigh, over the brim 

 of the pelvis, and takes the name of femoral. It descends 

 the middle of the thigh, between the vastus internus and 

 adductor muscles, then dips into the popliteal space, beneath 

 the gastrocnemius, and divides there into the anterior and 

 posterior tibial arteries. 



The posterior tibial passes down, as its name implies (i.e. 

 behind the leg), and goes to the sole between the internal 

 malleolus and the os calcis. It gives off, almost at its origin, . 

 a long branch, called the peroneal artery, which runs down 

 behind the outer side of the leg. 



