1 68 EQUINE ANATOMY. 



The SEBACEOUS GLANDS empty into the hair follicles or on the 

 skin independently. They consist of vesicles filled with fatty and 

 epithelial tissue, opening into a common duct. Their function is 

 lubrication and protection, as well as preservation of the elasticity 

 of the hair. 



THE HORNY PARTS. 



These comprise the chestnuts, ergot and hoofs. 



The Chestnut is a small growth of epithelial tissue, oval in 

 form, at the inner side of the upper metatarsal region, where it is 

 smaller, and at the inner side of the forearm. 



The Ergot is a similar structure attached to the skin of the fet- 

 lock. 



The Hoof. The hoof is the complicated apparatus surround- 

 ing the third or distal phalanx, navicular bone, and part of the 

 second phalanx. The bones, articulations, muscles, nerves and 

 vessels may all be found under their headings. It also consists 

 of the complementary apparatus, keratogenous membrane and 

 hoof proper. 



THE COMPLEMENTARY APPARATUS. 



This consists of the fbro-cartilages, two in number, united be- 

 hind and below by the plantar cushion. 



The Cartilages are two in number, attached in front to the 

 anterior lateral ligament, behind to the basilar and retrossal proc- 

 esses and plantar cushion; they are thin above, with a notch be- 

 hind for vessels, thick below, concave internally, with vascular 

 foramina, and convex externally, also with foramina for vessels. 



They are composed of fibrous and cartilaginous tissue. 



The Plantar Cushion is wedge-shaped, lying between the car- 

 tilages and below the insertion of the perforans. 



The superior surface lies on the expansion of the perforans, and 

 is attached by bands to the ergot, metacarpus and os pedis. The 

 inferior surface is covered by the keratogenous membrane, and 

 shows the pyramidal body moulded on the frog with its apex for- 

 ward and two diverging arms behind. Its base terminates in two 

 bulbs. 



The summit is attached to the plantar surface of the os pedis. 



The lateral borders are attached to the cartilages. 



Its structure is of fibrous, elastic and adipose tissue, with ves- 

 sels and nerves. 



