CHAPTER VII 
DISEASES ARISING FROM FAULTY 
CONFORMATION 
A. SAND-CRACK. 
Definition.—A_ solution of continuity of the horn of the 
foot, occurring usually in the wall, and following the 
direction of the horn fibres. 
Classification.—It is usual to classify sand-cracks accord- 
ing to— 
(a) Their Position.—Toe-crack when occurring in the 
middle line of the horn of the toe, and quarter-crack when 
occurring in the horn of the quarters. 
Sand-crack of the frog and sand-crack of the sole may 
also each be met with. They are, however, of rare occur- 
rence, and are seldom serious enough to merit special 
attention. 
The toe-crack is met with more often in the hind-foot 
than in the fore, while the quarter-crack more often than 
not makes its appearance in the fore-foot, and is there, as 
a rule, confined to the inner side. The reasons for these 
positions being so affected we shall deal with when treating 
of the causes of sand-crack in general. It is interesting to 
note that the portions of wall known as inside and outside 
toe are seldom affected. 
(b) Their Length.—Complete when they extend from the 
coronary margin of the wall to its wearing edge; Incom- 
plete when not so extensive. 
(c) Their Severity.—Simple when they occur in the horn 
only, and do not implicate the sensitive structures beneath ; 
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