142 THE MYOLOGY OF THE RAVEN. 



fibre-cartilaginous loop developed ; one end of this is 

 attached to the middle point of the posterior aspect of 

 the internal condyle of the humerus, while its other end 

 is fast to the ulnar side of the base of the olecranon pro- 

 cess. We will call this the humero-ulnar pulley. Now, 

 the origin of the flexor carpi ulnaris, the muscle under 

 consideration, is concerned with this very structure, for 

 we find that the muscle arises by two strong tendons ; 

 the one on the side towards the olecranon process, pass- 

 ing through the humero-ulnar pulley, makes fast to the 

 back of the internal condyle of the humerus; while the 

 outer tendon attaches itself to the same protuberance, 

 but at its outer aspect, and without the " pulley." 



These tendons are somewhat flattened, and each about 

 a centimetre long, when they merge into a strong, fusi- 

 form muscle, occupying rather more than the posterior 

 half of the under side of the forearm. From the an- 

 terior apex of this muscle a powerful and subcylindrical 

 tendon stretches directly to the back of the ulnar e ossi- 

 cle of the carpus, where it makes an extensive attach- 

 ment. Just before reaching this ossicle the tendon of 

 the flexor carpi ulnaris differentiates off a small tendi- 

 nous slip, which, passing through a fibrous loop at the 

 ulnar side of the carpus, goes obliquely downwards to 

 the tendon of the flexor digitorum profundus, and 

 merges with it at a point about opposite the distal apex 

 of the pollex digit ; or, more strictly speaking, is con- 

 tained in the same sheath with this tendon of the flexor 

 digitorum profundus tendon as far as the anterior rim 

 of the proximal phalanx of the index digit, where this 

 offshoot becomes inserted. 



In its action this muscle is a powerful flexor of the 

 hand upon the forearm, and its tendinous offshoot at 

 the carpus is not an inefficient aid to the action of the 



