The Anterior Limb. 215 



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 ten- 

 , don 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 metacarpophalan- 

 geal joints. 



Bloodvessels and Nerves of the Arm and Forearm. 



The deep artery of the arm (p. 209), a branch of the axillary, 

 passes between the coracobrachialis and the teres muscles to the 

 lateral surface of the shoulder, giving branches to the deltoideus 

 and to the proximal ends of lateral and long heads of the triceps. 

 The vessel continues on the lateral side of the medial head, of the 

 triceps and passes to the lateral head of the brachialis as the 

 radial collateral artery. Posterior, and occasionally anterior, 

 circumflex arteries to the head of the humerus arise from the deep 

 artery or separately from the brachial. 



*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 sur- 

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

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



