THE CONSTRUCTION OF THE HORSE 139 



front and back of the limb forming the flexor and extensor 

 tendons. It is of some importance to note that there is an 

 absence of flesh or muscle below the knee or hock, hence 

 it follows why wounds and other injuries are usually so 

 slow in healing. 



The muscles of the neck, back, loins, and quarters are 

 long and well developed, whilst those in the limbs have 

 their tendinous prolongations gliding through lubricating 

 sheaths at the joints, either at the front or the back of 

 the limbs. Each muscle has its own particular functions 

 to fulfil, and it may either act in consort with other 

 muscles or in opposition to such in fulfilling its functions. 



All the muscles are richly supplied with pure blood by 

 the arteries and by veins for carrying away the impure 

 blood. Their power of movement is regulated by their 

 nerve supply. 



The more highly developed the muscular system, the 

 more speciaUsed the functions in this particular area. 



Internal Structure of a Horse 



The nervous system comprises the brain and spinal 

 cord, and the nerves issuing to and from these structures. 

 The brain is lodged within the cranial cavity, and it 

 occupies a very sheltered position, but in spite of the 

 protection thus afforded it, it is hable to injury, to disease, 

 and to participate in functional derangement. It is 

 composed of a right and left hemisphere, the whole con- 

 stituting the cerebrum, whilst there is a smaller portion 

 of the brain known as the cerebellum, beneath which lies 

 the medulla oblongata and the pons varolii, both of 

 which look like expanded portions of the spinal cord and 

 with which they are in direct continuity. From the base 

 of the brain twelve pairs of nerves arise, such as the nerves 

 of smeU, sight, taste, and so forth 



The brain has three protective coverings, the outermost 

 of which is thick and fibrous. The blood supply to the 

 brain is of a very complex nature. 



