Page 115 - Adams and Stashak's Lameness in Horses, 7th Edition

Examination for Lameness 81

racehorses to musculoskeletal injuries and contribute to
a multitude of lameness problems in the palmar aspect
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of the foot.
26,29,31
Faults in Conformation of the Forelimbs
Base‐narrow
In base‐narrow conformation, the distance between
the center of the feet on the ground is less than the dis­
tance between the center of the limbs at their origin in the
chest when viewed from the front (Figure 2.15). This is
often seen in horses with large chests and well‐developed
pectoral muscles, such as the Quarter horse. This confor­
mation may be accompanied by a toe‐in (pigeon‐toed) or
toe‐out (splay‐footed) conformation. Base‐ narrow con­
formation inherently causes the horse to bear more
weight on the outside of the foot than on the inside.

Base‐wide
In base‐wide conformation, the distance between the
center of the feet on the ground is greater than the dis­ Figure 2.16. Base‐wide conformation. The distance between the
tance between the center of the limbs at their origin in center lines of the feet is greater than the distance between the center
lines of the limbs at the chest.
the chest when viewed from the front (Figure 2.16). This
condition is found most commonly in narrow‐chested
horses and may be accompanied by toe‐out (splay‐
footed) position of the feet. Base‐wide, toe‐out confor­
mation usually causes winging of the limb to the inside
(Figure 2.17). Base‐wide conformation may force the
horse to land on the inside of the foot, increasing weight‐
bearing forces on the inside of the foot and entire limb.

toe‐in or Pigeon‐toed
Toe‐in is the position of the feet in which the toes
point toward one another when viewed from the front
(Figures 2.18 and 2.19). Its point of origin can be as
high as the chest or as low as the fetlock down. It is
often accompanied by a base‐narrow conformation but
rarely is present when the horse is base‐wide. In the

Figure 2.15. Base‐narrow conformation. The distance between
the center lines of the limbs is greater than the distance between the Figure 2.17. Winging, which may cause interference, is caused
center lines of the feet on the ground. by a toe‐out position of the foot.