THE FOOT • 677 



basis. If any doubt exists as to the function of the laminae in 

 supporting the weight of the horse's body, it is only necessary 

 to look at the processes which occur in them as the result of 

 disease. Laminitis is often attended by separation of the 

 laminae, when, the horse's weight being no longer properly sup- 

 ported, the pedal bone under its influence is actually forced 

 through the sole of the foot. 



The Use of the Bars. — The inflected portion of the wall, known 

 as the ' bars,' runs, as we have previously mentioned, forwards 

 under the foot instead of completing the circle of the wall. 

 The object of this non-completion of the ring the wall origin- 

 ally gave promise of forming, is to allow of expansion of the 

 foot by making room for the elastic posterior foot — viz., the 

 plantar cushion and foot-pad. The explanation why the wall is 

 turned in instead of ending abruptly, is to afford a solid bearing 

 to the posterior part of the foot, to give additional strength, and 

 to secure a more intimate union with the sole. The bars, being 

 part of the wall, are intended to bear weight, and in conse- 

 quence in the foot of the wild horse and zebra they present the 

 most extraordinary development. 



The Use of the Sole is quite clear : it is to afford protection to 

 the sensitive parts above. Its normally concave shape (Figs. 229 

 and 230) proves that it is not intended to bear on the ground 

 over its general surface, and the acute lameness which results 

 from a stone in the foot gives further proof, if any were required, 

 of its indifferent weight-supporting properties ; that margin, 

 however, in contact with the wall can bear weight, as there is 

 no sensitive part immediately above it (see Figs. 229, 230). 

 Under the influence of the body weight the sole becomes slightly 

 flatter, especially that portion of it situated posteriorly in the 

 horns of the crescent. When the expansion of the foot is 

 studied, the object of this flattening will be more apparent. 



The Use of the Foot-pad. — This is one of the chief anti-con- 

 cussion mechanisms in the foot ; it is there to prevent jar, and it 

 does so by receiving, in conjunction with the posterior wall, the 

 impact of the foot on coming to the ground ; this is imparted to the 

 plantar cushion, and through the lateral cartilages to the wall of 

 the foot, which bulges or, as it is termed, expands (see Fig. 239). 

 In breaking the jar (not only to the foot but to the whole limb), it 

 is assisted by its elastic, rubber-like nature. The foot-pad needs 

 for its perfectly healthy condition contact with the ground ; it is 

 strange that in this respect two structures situated side by side 

 — viz., the sole and pad — should be so opposed in function. If 

 the foot-pad be kept off the ground, the'part atrophies, the heels 

 contract, the foot is rendered smaller, and the pad becomes 

 diseased. This wasted condition of the pad and narrow foot may 



