EXTENSOR COMMUNIS DIGITORUM 



325 



tened cylindrical shape, diverge to their respective fingers. Opposite the heads of 

 tlie metacarpal l^ones, each tendon gives off fil)rous bands to the lateral ligaments 

 of the corresponding metacarpo-phalangeal yAwi. L'pon the first i)halanx the tendon 

 expands into a broad aponeurosis which fits closely by its concave anterior surface 



Fig. 277.— Tendons upon the Dokslm of the Hand. 



Extensor oasis metacarpi pollieis 

 Extensor brevia pollieis 



Posterior annular ligament 



Extensor carpi radialia brevior 



Extensor carpi radialis longior 



Extensor longus pollieis 



First dorsal interosseous 

 Adductor pollieis 



- Extensor carpi 

 ulnaris 



Extensor communis 

 digitorum 



Extensor minimi 

 digiti 



Extensor indicia 



Tendon of first dorsal interosseous 



Attachment of extensor communis 

 digitorum to second phalanx 



Attachment of extensor communis 

 digitorum to third phalanx 



upon the back of the bone and affords attachment ])y its lateral margins to other 

 muscles. After passing over the back of the first jdialangeal j( )int, the central portion 

 of tliis aponeurosis is inserted into the base of the second i)halanx, while its lateral 

 portions converge and, passing over the second })halangeal joint, are attached to the 

 back of the base of the ungual phalanx. A transverse band usuallv unites the 



