142 Anatomy of the Rabbit. 



(d) The palmaris. Origin: Medial epicondyle. Insertion: Super- 

 ficially on the volar fascia. This extremely slender muscle 

 lies between the superficial portion of the profundus and 

 the flexor carpi ulnaris. 



(e) The flexor digitorum profundus. Origin in four portions: 



Superficial portion: Medial epicondyle. 



Radial portion: \'entral surface of the radius. 



Middle portion: Ventral surface of the ulna. 



Ulnar portion: Medial epicondyle in common with (c) 

 Insertion : By five tendons on the bases of the ungual 

 phalanges. 



(f) The flexor carpi ulnaris. Origin: Medial epicondyle and 

 medial surface of the olecranon, forming two short but 

 separate heads. Insertion: Pisiform bone. 



7. Muscles arising from the bones of the hand and inserted on the 

 individual digits: 



(a) The flexor digiti quinti. Origin : Pisiform bone and tendon 

 sheath of the flexor digitorum profundus. Insertion: 

 Sesamoid bones of the metacarpophalangeal joint of the 

 fifth digit, extending to the ungual phalanx. 



(b) The lumbricales. Origin : From the point of division of the 

 tendon of the flexor digitorum profundus. Insertion : First 

 phalanges of the second to fifth digits. 



(c) The interossei. Origin : In pairs from the bases of the second 

 to fifth metacarpals and related portions of the carpal bones. 

 Insertion : Sesamoid bones of the metacarpophalangeal 

 joints. 



Bloodvessels and Nerves of the Arm and Forearm. 



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

 passes distad on the medial surface of the arm between the biceps and 

 the anconaeus medialis. 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 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 ventromedial 

 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 vflna obliquely from its 

 origin, reaching in this way the lateral border of the flexor carpi ulnaris, 



