iS4 THE SURGICAL ANATOMY OF THE HORSE 



lower part of the tliigh, a hand's breadth above the point of the 

 hock." 



It should be remembered that the anterior tibial nerve is here much 

 more deeply seated, and lies beneath the extensor pedis on the flexor 

 metatarsi muscle. This will be made clear by a reference to Plate XXV. 

 An incision should be made in this situation through the skin and 

 superficial fascia. The deep fascia will then be seen, and care must now 

 be taken to avoid the musculo-cutaneous nerve, which runs along the line 

 of apposition of the extensor pedis and peroneus, and the position ot 

 which is very superficial. A reference to the seat in section (Plate XXV.) 

 will reveal the relative positions of the two nerves. The incision in the 

 deep fascia should be made along the posterior border of the extensor 

 pedis, and the operator should then dissect carefully along the posterior 

 face of the muscle, when the anterior tibial nerve will be found lying on 

 the flexor metatarsi. During this dissection the musculo-cutaneous nerve, 

 with the posterior lip of the deep fascia, should be drawn backwards. 

 Care must be taken when dealing with the anterior tibial nerve not to 

 injure the anterior tibial vessels, which are in close proximity to it (see 

 Plate). 



In this seat it will at once be seen that the nerve is in a more difficult 

 situation for operative purposes. At the same time the seat has an 

 advantage, inasmuch as there is no danger of injuring the nerves which 

 supply the extensor pedis and flexor metatarsi. In the upper seat, how- 

 ever, the anterior tibial nerve is much more easily found, and by making 

 a fairly long cutaneous incision (to which there can be no objection) it is 

 possible to avoid the branches referred to, since they are usually given 

 off immediately the nerve passes in between the peroneus and extensor 

 pedis, and are more deeply seated than the parent nerve. 



One or two simple interrupted sutures should be inserted in the 

 cutaneous opening, and the seat dusted over with dry dressing in the 

 usual way, when the animal may be allowed to rise. 



Frequently after Bossi's double neurectomy, or anterior tibial neurec- 



