216 ANATOMY OF THE RABBIT. 
point—a short distance in front of the elbow—into the radial and 
ulnar arteries. Its chief branches on the arm are the ulnar 
collateral arteries (superior, middle, and inferior) to the muscles 
and the elbow joint. 
The radial artery (a. radialis) passes distad on the ventro- 
medial border of the radius, in company with the median nerve, 
lying at first between the flexor carpi radialis and the radial portion 
of the flexor digitorum profundus. Toward the distal end of the 
radius it crosses the ventral surface of the tendon of the flexor carpi 
radialis, and appears in a superficial position on the medial border 
of the carpus. It reaches the volar surface of the hand after passing 
obliquely across the tendon of the flexor digitorum sublimis. 
The ulnar artery (a. ulnaris) crosses the ulna obliquely from its 
origin, reaching in this way the lateral border of the flexor carpi 
ulnaris, along which it passes to the end of the forearm and to the 
ulnar side of the pisiform bone. It passes to the ventral surface 
of the fifth digit, and then turns across the hand, forming the volar 
arch. 
**The single brachial vein (v. brachialis) accompanies the brachial 
artery and lies behind it. It is formed in front of the elbow by the 
union of two vessels, the radial and ulnar veins, which accompany 
the corresponding arteries and join one another at the point of 
separation of the latter. The radial vein anastomoses with the 
radial portion of the cephalic at a point distal to the middle of the 
forearm. 
The cephalic vein (v. cephalica) is a large superficial vessel 
appearing on the dorsal surface of the forearm. From the radial 
side of the latter it receives a large tributary which anastomoses 
with the radial vein. It is accompanied by branches of the super- 
ficial ramus of the radial nerve. It passes to the front of the arm 
across the angle of the elbow, lying at first on the anterior margin 
of the lateral head of the brachialis, and afterwards on the lateral 
surface of the arm between the abductor brachii superior and the 
anconaeus lateralis. It disappears from this surface in the trian- 
gular space enclosed by these muscles and the insertion of the 
levator scapulae major, receiving at this point a large tributary from 
the shoulder. It appears on the medial surface of the shoulder at 
