Page 125 - Adams and Stashak's Lameness in Horses, 7th Edition

Examination for Lameness 91

Saddlebred when these horses are used for show because
the hoof wall is allowed to grow excessively long.
VetBooks.ir sent in some horses. This may be congenital or develop­
A unilateral contraction of one forefoot may be pre­
mental, but it is not known whether it is a heritable
abnormality. The contracted foot may or may not even­
tually show lameness, but it should be regarded as an
undesirable feature. A small foot on one side with a nor­
mal opposite foot may be normal for certain horses, but
it may also indicate a subclinical lameness in the foot
with the steeper hoof angle. This is often referred to as
42
“mismatched” or “uneven” feet. In a recent study of
Dutch Warmblood horses, the prevalence of “uneven”
front feet was 53% with weak genetic correlations.
However, the study concluded that reducing the occur­
rence of uneven feet by selection was possible without
limiting progress in sport horse performance. 15

Buttress Foot
“Buttress foot” is a swelling above the dorsal surface
of the hoof wall at the coronary band (Figure 2.40). This
swelling may be from low ringbone or a fracture of the
extensor process of the distal phalanx (coffin bone).
A conical deformity of the toe from the coronary band
to the ground surface occurs due to the deformed hoof Figure 2.41. Front view of a horse with a buttress foot associ-
growth associated with chronic swelling at the coronary ated with a large extensor process fracture of the distal phalanx.
band. This often results in a triangular or pyramidal The foot has assumed a triangular or pyramidal shape.
shape to the foot (Figure 2.41).

CluB Foot
A “club foot” usually refers to a foot with a foot axis
greater than or equal to 60° (Figure 2.42). A unilateral
club foot may be due to an injury that has prevented
proper use of the foot (disuse due to chronic lameness)
or from a flexural deformity involving the deep digital
flexor tendon, seen primarily in foals. It may be develop­
mental or acquired and may or may not contribute to a
lameness problem. 7,29

Figure 2.42. Young horse with a club foot due to a flexural
deformity of the deep digital flexor tendon. There can be many
causes of a club foot and not all contribute to lameness.

ACKNOWLEDGMENT
The authors thank Cherry Hill for her contributions
Figure 2.40. Buttress foot. to this chapter in the previous edition.