270 ANATOMY OF THE RABBIT 



the largest (posterior) passes between the coracobrachialis and the 

 teres muscles, giving branches to the deltoideus and to the proximal 

 ends of the lateral and long heads of the triceps. It then continues 

 (ramus descendens) on the lateral side of the medial head of the 

 triceps and passes to the lateral head of the brachialis, near the 

 elbow, as the radial collateral artery. 



The distal part of the distribution of the vessel just described 

 corresponds with the distal part of the deep or superior profunda 

 artery of the human subject. The deep artery (a. profunda brachii) 

 of the rabbit is a small and variable vessel originating from the 

 beginning of the brachial artery. It lies behind the radial, median, 

 and ulnar nerves, accompanying the first for a short distance, and 

 supplies the long head of the triceps. 



The brachial artery (a. brachialis), the continuation of the 

 axillary, passes distad on the medial surface of the arm between the 

 biceps and the medial head of the triceps. Crossing to the anterior 

 surface of its distal extremity, it passes beneath the head of the 

 pronator teres to the medial surface of the radius, dividing at this 

 point— a short distance in front of the elbow — into the median and 

 ulnar arteries. Its chief branches on the arm are the ulnar col- 

 lateral arteries (superior, middle, and inferior) to the muscles and 

 the elbow-joint. It soon gives off an interosseous branch which 

 runs along between radius and ulna. 



The median artery (a. medianus) 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. A small radial artery may be given 

 off before the bifurcation into median and ulnar and may run superfi- 

 cially distad in the forearm. Toward the distal end of the radius the 

 median artery crosses the ventral surface of the tendon of the flexor 

 carpi radialis, and appears in a superficial position on the medial bor- 

 der of the carpus after giving off a rather large branch, the medianora- 

 dial artery. Both vessels reach the volar surface of the hand, the 

 median passing obliquely across the tendon of the flexor digitorum 

 sublimis and curving laterad to anastomose with the ulnar artery. 

 It thus forms a volar arch from which branches extend into the 

 more lateral digits. (It may be noted that the parts supplied in man 

 by the radial artery are here supplied mainly by the median vessel.) 



