THE PASTERN JOINT. 37 



in the ligamentous pit of the lower end of the metacarpus, the 

 lower to the side of the upper end of the suffraginis bone.* 



2. The Pastern Joint, 



Consisting of only two articular surfaces, the lower end of 

 the suffraginis and the upper end of the coronet bones, is the 

 simplest joint of the foot. The suffraginis bone possesses a 

 convexity, the coronet bone a corresponding concavity, which is 

 completed at the back by tendinous and ligamentous structures. 

 The ligaments of the coronet joint are : — 



(1) A capsular ligament, or rather, a synovial membrane 

 (fig. 10,/), attached to the borders of the respective articular 

 surfaces. Its outer sheath is anteriorly and laterally fairly 

 strons:, in front it is attached to the extensor tendon of the 

 foot, and laterally to the lateral ligament ; posteriorly to the 

 cartilaginous mass formed by the tendons and ligaments there 

 inserted, at which point it is very thin and lax. 



(2) An inner and an outer lateral ligament (g). These are 

 short, but fairly strong, bands, arising from the sides of the lower 

 end of the suffraginis bone, and being attached to the lateral 

 surfaces of the upper part of the coronet bone. They are con- 

 tinued downwards and backwards as the postero-lateral liga- 

 ments of the coffin joint, and each eventually is inserted into 

 the end of the navicular bone of its own side, and into the 

 wing of the os pedis. 



(3) The posterior corono-suffraginal ligaments are four in 

 number. The two central Qi) arise from the sides of the rough 

 triangle at the posterior surface of the suffraginis bone about 

 its centre ; between them lies the lower part of the central 

 limb of the inferior sesamoidean ligament (superficial inferior 

 sesamoidean ligament). The lateral (li') arise from the sides of 

 the suffraginis boue, about its lower third, and are in contact, 

 on either side, with the terminal branches of the flexor pedis 

 perforatus tendon. They are weaker than the central, and are 



* Prof. Mettam considers it is doubtful if the lateral sesamoidean ligament 

 divides into two portions. He prefers rather to look upon that directed upwards, 

 as here related, as a portion of the lateral ligament of the fetlock joint, and the 

 lower portion inserted into the sesamoid as the true lateral sesamoid ligament. — 

 [Jno. a. W. D.] 



