POSTERIOR RADIAL ARTERY 423 



front of the radius, and approach the knee below the extensor 

 pedis. It divides into numerous branches, which are distributed 

 to the capsular ligament of the carpus and extensor muscles, 

 arastomosing with the interosseous branch of the posterior radial 

 artery. 



POSTERIOR RADIAL ARTERY. 

 (Fig. 162. 4.) 



The posterior radial is the continuation of the humeral artery. 

 It passes down the inner side of the fore-arm, with a vein and 

 nerve, inclining backwards beneath the flexor metacarpi internus, 

 and is sometimes described as dividing at the distal end of the 

 radius into large and small metacarpals ; it can be felt just behind 

 the insertion of the flexor brachii. It supplies twigs to the elbow 

 joint, which anastomose Avith those of the ulnar, and muscular 

 branches to the posterior region of the arm, with the following 

 named branches : — 



Interosseous. | Radio-palmar. 



Recurrent radial. 



The Interosseus artery of the fore-arm comes off near the 

 xadio-ulnar arch, through which it passes outwards, crossing the 

 posterior surface of the radius below the perforans. It then 

 <lescends in the radio-ulnar groove, covered by the extensor 

 suffraginis, and inosculates with the anterior radial, forming a 

 plexus above the carpus ; it yields branches to the elbow joint 

 and flexor muscles, also the nutrient radial, to supply the radius. 



The Recurrent radial artery is a small branch given off 

 just above the carpus ; passing outwards and downwards, under 

 the flexor metacarpi medius, it inosculates with the cubital and 

 forms the superior carpal arch, from which a branch descends in 

 the thickness of the annular ligament, to inosculate with the 

 radio-palmar, below the carpus, and form the inferior carpal 

 arch. 



The Radio-palmar or Small metacarpal artery is given off 

 at an acute angle. It passes the inner and posterior aspect of 

 the carpus, external to the posterior annular ligament, which 

 separates it from the large artery. About the head of the meta- 

 carpus it crosses from the inner to the outer side at the back of 

 the leg; inosculating with a descending branch from the superior 

 ■carpal arch, and so forming the inferior carpal arch, whence 



