LIGAMENTS AND MUSCLES OF THE HORSE. 47 



Insertion. — To the hecad of the iiinei- small metacarpal. 

 Action.— Same as preceding. 



4. Flexor Pedis Perforatus. 



Origin. From the internal condyle of the humerus. 



Insertion. To the lateral sides of the os coron?e (in two divi- 

 sions) 



Action - To flex the pastern, fetlock and knee successively. 



A^ote. — At the lower part of the radius, the tendon is reinforced 

 by a fibrous band from the back of the radius. It then 

 passes through the carpal sheath, in company with the deep 

 flexor. On arriving behind the fetloc'-, it forms a remark- 

 able ring, through which the deep flexor tendon plays. 



5. Flexor Pedis Perforans. 



Origin. — From the internal condyle of the humerus. 



Insertion. — To the semilunar crest of the os pedis. 



Action. — To flex the foot, pastern, fetlock, and knee-joints suc- 

 cessively. 



N'ote. — The tendon passes through the carpal sheath, close to 

 and in front of that of the superficial flexor. Above the 

 knee it is joined by the ulnaris and radialis accessorius 

 (which are in reality only portions of the perforans) ; and 

 below the knee it is reinforced by the check ligament. 

 The tendon then passes over the sesamoid pulley (through 

 the ring formed by the perforatus), over the glenoid cartil- 

 age and the navicular bone to its insertion, where it widens 

 out to form the plantar aponeurosis. 



6. Ulnaris Accessorius. 



7. PtADiALis Accessorius. 



These are really heads of the perforans, arising from the ulna, 

 and back of the radius respectively. 



Carpal Sheath. 



This is formed behind the carpus, and forms a tubular passage 

 for the flexors of the digit. It is bounded anteriorly by 



