60 THE BLOOD-VESSELS AND NERVES OF THE FOOT. 



over, and, in a certain sense, regulate the nutritive and secre- 

 tive processes, thus exercising a most important influence on 

 growth, in addition to serving as channels for the conveyance 

 of impulses which result in motion or sensation. The extra- 

 vascular portions of the foot, i.e., the horny tissues, are destitute 

 of nerves, so that cutting the horn of the hoof and the hairs 

 above it causes the animal no pain ; but the skin and the horn- 

 secreting structures, on the other hand, are freely supplied. 

 For this reason most diseases of the foot cause lively pain, 

 whether they result from bruising, pricks in shoeing, inflamma- 

 tion, contraction of the foot, or any (me of the many other 

 possible forms of injury. 



The nerves which supply the foot arise from the spinal cord, 

 and in the lower part of the limb, where they accompany the 

 digital artery and vein, are termed the digital nerves. 



Each digital nerve (fig. 36, 1) divides at the fetlock into 

 two twigs. The anterior (fig. 36, ^) passes obliquely down- 

 wards and forwards over the digital artery and vein, and splits 

 into a great number of small branches, which are distributed in 

 the skin, the coronary band, and the sensitive laminae. 



The posterior branch (figs. 36, 37, 3, and 38, ^) is the larger, 

 and lies behind the artery, which it accompanies as far as the 

 point where the latter forms the net-work in the pedal bone. 

 On its way to the plantar foramen it gives off a few twigs for 

 the skin (figs. 36 and 37,^), for the joints, and especially for the 

 sensitive frog and sensitive sole. The portion which accom- 

 panies the plantar artery into the pedal bone divides into very 

 fine branches, which run side by side with the small arterioles, 

 make their way out of the pedal bone, and are finally lost in 

 the lamina3 (fig. 38, 5). 



A third (middle) branch of the plantar nerve can sometimes 

 be distinguished running down immediately behind the vein 

 and supplying the coronet and sensitive laminae. In the horn- 

 secreting tissue, especially in the sensitive frog, peculiar 

 structures have been found connected with the nerves, which 

 are known under the names of Pacinian or Vater's corouscles. 



