138 THE HORSE 



femur (femoro-patellar articulation). To limit the degree 

 of concussion in this region discs of cartilage are inter- 

 posed between the opposing articular surfaces, the whole 

 being enclosed and supported by capsular and straight 

 ligaments. 



The stifle joint is frequently the seat of various injuries, 

 the principal one being slipped stifle (dislocation patella), 

 and this is commonly met with in foals and colts, but 

 also in adult animals, both horses and mules, more 

 especially those in poor condition. 



The hock joint — corresponding to the ankle in man — 

 is like that of the knee, composed of a number of joints 

 formed betw^een the lower end of the tibia and the large 

 and small bones of the hock, as well as the upper ends of 

 the large and small metatarsals ; but the principal articula- 

 tion is that between the lower end of the tibia and the 

 astragalus, or screw-bone of the hock. This is called the 

 true hock joint, and it allows a great degree of flexion, 

 and the greater this degree, the better the hock action. 

 The rest of the joints correspond to those in the fore limb. 



The Muscular System 



The muscular system of the horse is a well developed 

 one, and comprises the whole mass of muscle or flesh 

 attached to the skeleton upon which it is moulded. 

 Muscular tissue is divisible into two varieties, namely, 

 the striped or voluntary muscle, and the plain or in- 

 voluntary ; whilst a third variety forms the whole 

 substance of the heart, and is known as cardiac muscle, 

 in which the fibres are disposed in a special manner. 



The whole of the muscles on the skeleton are of the 

 striped variety, whilst plain muscle is found in the walls 

 of the stomach, intestines, etc. All the muscles of the 

 skeleton have what is known as an origin and an insertion, 

 and those of the limbs, particularly below the knee and 

 the hock, have long tendinous attachments, both to the 



