160 SURGICAL ANATOMY OF THE REGION 



(5) extensor minimi digiti ; (6) extensor carpi ulnaris. 

 The sy no vial membrane investing their anterior surfaces 

 being very thin and indistinct, is more frequently the 

 seat of ganglion than that of the flexor tendons. 



The tendons of the extensor muscles, having arrived 

 at the metacarpo-phalangeal articulation, receive the 

 tendons of the lumbricales and interossei, whilst at the 

 first phalangeal joint they divide into three fasciculi, the 

 central one being inserted into the base of the second 

 phalanx, and the two lateral passing on and reuniting, 

 are inserted into the base of the ungtial. They have no 

 distinct synovial sheaths. 



The radial artery at the wrist can be felt or seen beat- 

 ing between the tendons of the flexor carpi radialis and 

 supinator longus, where it is quite superficial and easily 

 secured. Accompanied by vense comites, it winds round 

 the outside of the wrist, to gain the first interosseous 

 space, when it enters the palm between the two heads of 

 the first dorsal interosseous, and is crossed by the exten- 

 sors of the thumb. It is readily secured at the base of 

 the well-marked hollow formed by these muscles. In 

 disarticulation of the metacarpal bone of the thumb it 

 stands a chance of being divided, but if the knife be kept 

 close to the bone it can be avoided. The most important 

 branch of the radial is the superficial volar, which ordi- 

 narily lies subcutaneously, and completes the superficial 

 arch. The other branches given off at the wrist supply 

 the carpus and dorsal aspects of the thumb ancl first 

 finger. 



The ulnar artery, at the wrist, lies with its venaa 

 comites on the radial side of the flexor carpi ulnaris, and 

 with its nerve to its inner side. 



Articulations of the Wrist-joint. These are the inferior 



