82 THE SURGICAL ANATOMY OF THE HORSE 



made is thus very small. The author has frequently performed this 

 operation, with a fair measure of success, but the effect is not so satis- 

 factory as that produced by some of the other methods of treatment ; 

 neither does it appeal to one as being very surgical, particularly so far 

 as the scraping part of the operation is concerned, since the operator is 

 working, as it were, in the dark. 



Closely allied to the above operation is another which has been 

 frequently performed in the treatment of this disease. This consists in 

 incising the skin and then slitting the coverings of the exostosis. To 

 this operation the term periosteotomy has been applied, and it was 

 performed with the object of relieving the pressure of the exostosis on 

 the sensitive structures covering it. Objection has been taken to the 

 term periosteotomy on the ground that there is little if any periosteum 

 covering the bones in this situation. A great proportion of the super- 

 ficial surfaces or the bones here is undoubtedly taken up in affording 

 attachments to ligaments. 



Other operations performed in the treatment of spavin are neu- 

 rectomy of the anterior and posterior tibial nerves and tenotomy of the 

 cunean branch of the tendon of the flexor metatarsi muscle. These 

 operations are described in the chapters dealing with the nerves and 

 tendons. The object in neurectomy is to destroy sensation in the part by 

 excising a portion of the nerve by which it is supplied, and in tenotomy 

 to relieve pressure on the area. 



THE METATARSAL BONES 



The Large Metatarsal Bone. — This bone bears a close resemblance to 

 the large metacarpal bone, but a distinction is easily made between the 

 two bones by the fact that the metacarpal bone is longer and in transverse 

 section is much the more cylindrical. It possesses a shaft and two 

 slightly expanded extremities. For descriptive purposes the shart may 

 be said to present four surfaces. 



