THE HORNY WALL. 



75 



and inclined towards each 

 middle posterior angle be- 

 ing open at the back for 

 the reception of the frog, 

 the two lateral facing for- 

 wards and grasping the 

 posterior prolongations of 

 the sole. 



The horny wall presents 

 an outer (anterior) smooth, 

 slightly ribbed, or undu- 

 lating surface, convex from 

 side to side (hg. 44), and 

 an inner (posterior) and 

 correspondingly concave 

 surface (figs. 47 and 48) : 

 an upper border in contact 

 with the cutis, and a lower 

 which marginates the sole. 

 The upper (fig. 44, a) is 

 o-enei'allv known as the 

 coronary border, whilst the 

 the plantar or bearing 

 border. 



For convenience of de- 

 scription the wall may be 

 divided by imaginary ver- 

 tical lines ; thus, one drawn 

 through the centre of 

 the hoof will divide the 

 wall into an inner and an 

 outer half (inner and outer 

 walls), or four lines may 

 be so drawn as to divide 

 the wall into five equal 

 parts, termed respectively 

 the toe, the inner and outer 

 quarters, and the inner and 

 outer heels. 



(a) The anterior portion 



other, forming three angles, the 



7/» 



Fig. 45.— Under suvface i)f right fore-fuot. a, a, 

 Ijearing surface of toe ; a. b, uf quarters ; b, c, of 

 heels ; d, commencement of bars ; e, lateral aspect 

 of bars ; f, sole ; f, seat of corn ; <j, white line, 

 which is seen to be reflected forwards between sole 

 and bars at g'; h. horny frog ; /, bulb or glome of 

 frog; k, bulb of heel; I, median lacuna or cleft of 

 frog ; m, lateral lacuna^ of frog. 



lower (figs. 45 and 46, a) is termed 



/r d ^' 



Fig. 4G. Under surface of right liind-foot. The 

 lettering is as in tig. 45. 



or toe (fig. 44 from the point of the 



