SPRAIN OF SUSPENSORY LIGAMENT. 281 



crease of obliquity whicli is seen during rapid action is due to 

 the movements of the os coronse on the pedal bone, the articula- 

 tion between them admitting of extension to a much greater 

 degTee than any of the other phalangeal articulations. If it 

 be carefully noted, the movement between the os suffraginis 

 and metacarpal is almost confined to flexion ; that between the 

 suffraginis and coronse very limited in every way ; whilst the 

 formation of the inferior articular extremity of the os coronse 

 and the articular surface of the coffin bone admit of both 

 flexion and extension, the first movement being more limited 

 than the latter. To prove this by analogy, let the experi- 

 mentalist press a table with the bulb of his finger, and it will 

 be seen at once that the distal is much more capable of ex- 

 tension than the rest of the phalangeal articulations. The 

 comparison is a good one, as the articulations of the human 

 fingers and those of the pastern of the horse are very much 

 alike. It is a necessity to the well-being of the animal that 

 the greatest adaptability to extension should be at the ex- 

 tremity of the limb, as the greatest pressm-e is there ; in fact, 

 the pastern is a lever, extending from the fetlock to the foot, 

 and the greater the length it has, the more oblique it will be. 



The limb not only descends at the pastern during motion, 

 but it also ascends at the shoulder, where the body is suspended 

 upon it by the seratus magnus and other muscles. We have 

 thus a spring below and a spring above, — a wonderful and 

 beautiful provision to destroy the effects of concussion, which 

 would be fatal to the animal when aU the weight of his 

 body is thrown upon the fore extremity during galloping or 

 jumping. The hind extremity, unlike the fore one, is attached 

 to the trunk by means of an articulation — the hip-joint — be- 

 cause the forces that produce concussion are not applied to it 

 in the same degree as to the fore one ; the impulse of rapid 

 pace throwing the weight from the hind upon the fore extremity; 

 hence it is that one spring, namely, the inferior one, is 

 sufficient. 



The suspensory ligament being to all intents and purposes 

 inelastic, and the sesamoid bones firmly bound to it, to the 

 fetlock, and to the pastern, assists in supporting those parts of 

 the limb which are below it, namely, tlie pastern and the foot, 

 by forming a brace or stay, exactly in tlie same way as a 



