106 DISEASES OF THE HORSE'S FOOT 



symptoms of lameness still persist after section of the nerve. 

 In many cases this has been traced to the existence of an 

 abnormal nerve branch. In the higher operation this is 

 not so likely to be met with. That it may occur, however, 

 is shown by the following interesting case related by Harold 

 Sessions, F.R.C.Y.S. :* 



' In June of 1898 I saw a hunter suftering from navicular 

 disease. After carefully examining the leg, I advised the 

 owner to have the operation of neurectomy performed upon 

 him. This he decided to do, and the horse was sent to me 

 about the beginning of July. 



Fig. 62.— Dissected External Metacarpal Nefve and Branches. 



a, Metacarpal ; b, anterior plantar ; c, extra branch (probably from the 

 internal metacarpal), conveying sensation after division of the external 

 metacarpal. 



* The operation was performed in the ordinary way, with- 

 out any difficulty whatever. The wounds healed nicely, 

 but the horse still continued to go lame. Careful examina- 

 tion showed that there was still sensation on the outside of 

 the foot. Thinking that possibly there might be two 

 external metacarpal nerves, the horse was again cast, the 

 operation being performed slightly lower down. Only the 

 main branch of the external metacarpal nerve could be 

 found. A piece of this was taken out, and the horse let up. 

 On examination, sensation was still found in the posterior 

 part of the outside of the foot. It was very evident that 

 there was some abnormal distribution of the nerve, as 

 sensation was still being conveyed to that part of the foot. 



' As the horse was absolutely useless, and would have to 



* Journal of Comjiarative Pathology and Tlierajjeutlcs, vol. xii., 

 p. 343. 



