Page 152 - Adams and Stashak's Lameness in Horses, 7th Edition

118 Chapter 2

should avoid the sesamoid bones and be loose enough to
avoid excessive pressure to the flexor tendons and sus­
VetBooks.ir be forcibly flexed.
pensory ligament. The fetlock and phalanges should not
Alternatively, the tip of the toe can be held so the
pastern and fetlock joints are extended and the hock is
flexed (Figure 2.107). It may also be beneficial to gradu­
ally flex the tarsus to its fullest extent over a 15‐second
period to avoid resentment by the horse. In some cases
in which the horse tends to lean away from the exam­
iner, it may be helpful to place the horse adjacent to a
solid support (i.e. wall or fence) or have an assistant
provide counterbalance to the tuber coxae of the oppo­
site hip. Once the tarsus is in full flexion, it is held in this
position for 30–60 seconds, the limb is released gradu­
ally, and the horse is trotted off.
A positive hock flexion test is indicated by an increase
in lameness of the flexed limb. However, increased lame­
ness of the opposite limb (standing limb) is thought to
occur with some upper limb lameness problems (sacro­
iliac problems). The first few steps the horse takes after
this test are often the most important. If there is any
question regarding the validity of the flexion test, it
should be repeated. Two of the most common errors in
Figure 2.105. Flexion of the upper forelimb can be performed performing this test are not obtaining full tarsal flexion
by grasping the antebrachium and foot and pulling the limb caudally. and spooking the horse so that it balks at the onset of

Figure 2.106. Hock or tarsal flexion (spavin) test. The hindlimb is flexed so that the metatarsus is approximately parallel to the ground.
This test is not specific for the tarsus because it flexes both the stifle and the fetlock to some degree.