Page 116 - Adams and Stashak's Lameness in Horses, 7th Edition

82 Chapter 2

VetBooks.ir

Figure 2.18. Base‐narrow, toe‐in conformation.

Figure 2.20. Base‐narrow, toe‐out conformation.

chest, but the condition can be associated with outward
rotation of the fetlock. It may be accompanied by either
base‐wide or base‐narrow conformation. As with a toe‐in
conformation, it may be controlled or partially corrected
by corrective trimming or shoeing. The flight of the foot
goes through an inner arc when advancing, contributing
to interference with the opposite forelimb (Figure 2.17).

Base‐narrow, toe‐in ConFormation
Base‐narrow, toe‐in conformation causes excessive
strain on the lateral collateral support structures of car­
pus, fetlock, and phalangeal joints (Figure 2.18). It often
causes paddling and appears to be a common conforma­
tional abnormality.

Base‐narrow, toe‐out ConFormation
Base‐narrow, toe‐out conformation is one of the worst
types of conformation in the forelimb (Figure 2.20). The
Figure 2.19. Horse with a slight varus deviation of the distal closely placed feet, combined with a tendency to wing
limb. Slight toe‐in or pigeon‐toed conformation is relatively common inwardly from the toe‐out position, commonly cause limb
and does not appear to contribute to lameness in many cases. interference or plaiting. The hoof breaks over the inside
toe, swings inward, and lands on the outside wall, con­
young foal, the condition may be seen as the result of an tributing to increased strain on the limb below the fetlock.
angular limb deformity. Proper trimming and corrective The base‐narrow limb position places the weight on the
shoeing of the feet may prevent worsening of the condi­ outside wall, as with base‐narrow, toe‐in conformation.
tion, especially in growing horses. One study document­
ing variations in conformation in Swedish Warmblood
horses found a 50% frequency of mild toe‐in conforma­ Base‐wide, toe‐out ConFormation
tion in elite sport horses, suggesting that minor devia­ When a horse is base‐wide, the feet usually toe out.
tions do not impair soundness or performance. 22 The base‐wide conformation places the greatest stress
on the inside of the limb (Figure 2.21). The foot usually
breaks over the inside toe, wings to the inside, and lands
toe‐out or sPlay‐Footed
on the inside hoof wall. Interference is common, similar
In a toe‐out or splay‐footed conformation, the toes to any type of toe‐out conformation. Some horses,
point away from one another when viewed from the especially those with base‐narrow, toe‐out conforma­
front (Figure 2.20). The point of origin is usually at the tion, tend to place one foot directly in front of the other.