ULNAR ARTERY. 



295 



The Radialis indicis is also situated between the abductor indicis 

 and adductor pollicis, and runs along the radial side of the index 

 finger, forming its collateral artery. This vessel is frequently a 

 branch of the princeps pollicis. , 



The Interossece, three or four in number, are branches of the 

 deep palmar arch ; they pass forwards upon the interossei muscles 

 and inosculate with the digital branches of the superficial arch, 

 opposite the heads of the metacarpal bones. 



The Perforantes, three in number, pass directly backwards be- 

 tween the heads of the dorsal interossei muscles, and inosculate with 

 the posterior interosseous arteries. 



ULNAR ARTERY. 



The Ulnar artery, the other division of the brachial artery, crosses 

 the arm obliquely to the commencement of its middle third ; it then 

 runs down the ulnar side of the fore-arm to the wrist, crosses the 

 annular ligament, and forms the superficial palmar arch, which 

 terminates by inosculating with the superficialis volas. 



Relations. In the upper or oblique portion of its course, it lies 

 upon the brachialis anticus, and flexor profundus digitorum ; and is 

 covered in by the superficial layer of muscles of the fore-arm and 

 the median nerve. In the second part of its course, it is placed 

 upon the flexor profundus, and pronator quadratus, lying between 

 the flexor carpi ulnaris and flexor sublimis digitorum. While cross- 

 ing the annular ligament it is protected from injury by a strong ten- 

 dinous arch thrown over it from the pisiform bone ; and in the palm 

 it rests upon the tendons of the flexor sublimis, being covered in by 

 the palmaris brevis muscle and palmar fascia. It is accompanied 

 in its course by the vena? comites, and is in relation with the ulnar 

 nerve for the lower two-thirds of its extent. 



Plan of the relations of the Ulnar Artery : 



In front. 

 Deep fascia, 



Superficial layer of muscles, 

 Median nerve. 



In the Hand. 



Tendinous arch from the pisiform bone, 

 Palmaris brevis muscle, 

 Palmar fascia. 



Inner side. 



Flexor carpi ulnaris, . 

 Ulnar nerve (lower two- 

 thirds.) 



Ulnar Artery. 4 



Outer side. 



Flexor sublimis digito- 

 rum. 



Behind. 



Brachialis anticus, 

 Flexor profundus digitorum, 

 Pronator quadratus. 



In the Hand. 

 Annular ligament, 

 Tendons of the flexor sublimis digitoruin. 



