132 THE HOKSE IN HEALTH AND DISEASE 



The plantar cushion is the chief elastic organ. It is a buffer 

 of fibro-elastic tissue, situated between the horny frog below 

 and the deep flexor tendon above. 



The lateral cartilages comprise the other two elastic organs. 

 They were described with the bones of the foot. 



The pododerm, or foot-skin, is the collective term used for the 

 sensitive organs of the foot. It covers the foot in a manner similar 

 to that in which the skin envelops other parts of the body, but is 

 relatively thicker. Instead of producing the epidermis and hair, 

 it gives rise to the horn. When exposed it is found to be a red, 

 sensitive tissue, and is commonly called the "quick." For con- 

 venience the pododerm is divided into the perioplic band, the 

 coronary band, the sensitive laminae, the sensitive sole, and the 

 sensitive frog. Each of these parts secretes a corresponding horny 

 part for protection. 



The perioplic band is a narrow band of flesh running around 

 the hoof -head just above the coronary band. From the fine 

 villi on the surface of this band the periople, or hoof varnish, is 

 secreted. This substance is thin, hard, and brittle when dry, 

 its function being to hold moisture and keep the hoof soft and 

 elastic. 



The coronary band is a bolster-like structure, about 1 inch 

 wide, which extends entirely around the foot from the bulb of 

 one heel to that of the other. It lies in a groove at the upper 

 border of the hoof. From it the horny wall grows. 



The sensitive laminae consist of a large number of fleshy leaves, 

 longer at the toe than at the heel, that correspond with laminse of 

 the wall. 



The sensitive sole covers all the lower surface of the foot except 

 the plantar cushion. It is covered with villi which secrete the 

 horny sole. 



The sensitive frog covers the lower surface of the plantar cush- 

 ion and secretes the horny frog. 



The hoof is the protective organ of the foot. It is the horny 

 case or box enclosing the sensitive structures. Numerous minute 

 fibers resembhng hairs firmly bound together make up the hoof. 

 From the standpoint of horseshoeing it is next in importance to 

 the shoe; from that of utility it is paramount, as it is a reliable 

 guide to the condition of the important parts which it covers. 

 As the hoof is developed with the skin at the hoof-head^ it is readily 



