218 CIRCULATORY SYSTEM. 



from the radial; for it passes over the anterior annular liga- 

 ment of the carpus just at the radial side of the os pisiforme, 

 to which it is held by a small ligamentous noose; it then pro- 

 ceeds to the palm of the hand. Between the aponeurosis pal- 

 maris and the flexor tendons it forms that curve from the ul- 

 nar to the radial side of the hand called the Arcus Sublimis. 

 This curve commonly begins a little beyond the anterior mar- 

 gin of the annular ligament, and presenting its convexity for- 

 wards, terminates about the middle of the ball of the thumb at 

 its inner margin. 



The branches sent from the ulnar artery are as follow: 



1. The Recurrens Ulnaris arises from the ulnar about the 

 lower part of the tubercle of the radius, and, winding upwards, 

 is distributed in small branches to the muscles of the internal 

 condyle. One of its ramuscles goes between the internal con- 

 dyle and the olecranon process to anastomose with the arteria 

 anastomotica of the humeral. 



2. The Interossea arises from the ulnar, just below the other. 

 It is a large trunk, and proceeds but a little distance when it di- 

 vides into two principal branches, called anterior and posterior 

 interosseal arteries. 



a. The Interossea Anterior is much the larger; it runs in con- 

 tact with the interosseous ligament to the upper margin of the 

 pronator quadratus, giving off branches to the deep-seated mus- 

 cles of the fore arm in its course. Under the pronator it per- 

 forates the interosseous ligament, and distributes branches to the 

 back of the carpus and of the hand, which anastomose with 

 branches of the radial and posterior interosseal. 



b. The Interossea Posterior is sometimes a separate trunk, 

 arising from the ulnar just above the former. In either case it 

 soon perforates the interosseous ligament to get to the back of 

 the fore arm. Here it sends backwards a Recurrent Branch 

 (Recurrens Interossea) to the back of the elbow, which anasto- 

 moses with the recurrens ulnaris and radialis. It then proceeds 

 downwards, being deeply seated and distributed to the different 



