152 THE CAT. [CHAP. v. 



within the third part, and at ahout the middle of the arm divide 

 into two tendons. The more radial of these goes to the fourth digit, 

 and the more external (the paw being prone) to the third digit. 

 The third part arises highest up and superficially to the other parts. 

 It ends in a tendon which runs deeply and (passing at the wrist 

 through a separate synovial sheath) goes to the fifth digit (Fig. 80). 



The extensor indicts ct extensor sccundi internodil pollicis is a 

 very long and slender muscle, which springs from the outer margin 

 of the ulna, for almost its whole length, and from the outside of the 

 olecranon, being there covered in by the anconeus. It ends in two 

 delicate tendons, which go to the pollex and index digits respectively. 



The extensor ossis metacarpi pollicis is a large muscle arising from 

 a great part of the extensor surface of both the radius and the ulna, 

 and from the interosseous ligament. It is inserted into the first 

 metacarpal. Its origin on the ulna extends almost up to the 

 olecranon. On the radius it is conterminous with the insertion of the 

 supinator brevis. 



The extensor carpi ulnaris takes origin from the external condyle 

 of the humerus (below the other muscles there arising), and is 

 inserted, by a very strong tendon, into the fifth metacarpal. 



The supinator brevis is a rather deeply placed inuscle, which 

 comes from the outer condyle of the humerus and the upper part of 

 the ulna, and is inserted into the radius, wrapping it round some- 

 what from behind. 



The muscles of the fore-paw are numerous but small. The pollex 

 (which has no perforated flexor) is provided with a flexor brevis, 

 which extends from the trapezium, the trapezoides, and adjacent 

 deep palmar fascia, to be inserted into the base of the proximal 

 phalanx of the pollex. 



Opponens pollicis. This is a very small muscle, closely connected 

 with the last-named. Similar in origin, it is inserted into the 

 metacarpal of the pollex. 



An abductor brevis pollicis passes from the trapezium and annular 

 ligament of the wrist to the proximal phalanx of the pollex. 



A flexor brevis minimi digiti arises from the annular ligament and 

 unciforme, and is inserted into base of the first phalanx of the fifth digit. 



A few fibres with a similar origin, but inserted into the fifth meta- 

 carpal, constitute an opponens minimi digiti. 



The adductor minimi digiti is a relatively considerable muscle, 

 which arises from the palmar fascia at the root of the pollex, and is 

 inserted into the first phalanx of the fifth digit. 



An abductor minimi digiti arises from the outer side of the pisi- 

 forme, and is inserted by a long and delicate tendon into the ulnar 

 side of the proximal phalanx of the fifth digit (Fig. 80, Amd). 



The interossei are small muscles which arise from the sides of the 

 metacarpals and go to the sides of the proximal phalanges. When 

 the back of the paw is looked at (the other muscles being dissected 

 off) four interossei, called dorsal, are to be seen as follows : one on 

 each side of the third digit, one on the radial side of the index, and 



